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Configuration Files
Apache HBase uses the same configuration system as Apache Hadoop. All configuration files are located in the conf/ directory, which needs to be kept in sync for each node on your cluster.
backup-masters
Not present by default. A plain-text file which lists hosts on which the Master should start a backup Master process, one host per line.
hadoop-metrics2-hbase.properties
Used to connect HBase Hadoop’s Metrics2 framework. See the Hadoop Wiki entry for more information on Metrics2. Contains only commented-out examples by default.
hbase-env.cmd and hbase-env.sh
Script for Windows and Linux / Unix environments to set up the working environment for HBase, including the location of Java, Java options, and other environment variables. The file contains many commented-out examples to provide guidance.
hbase-policy.xml
The default policy configuration file used by RPC servers to make authorization decisions on client requests. Only used if HBase security is enabled.
hbase-site.xml
The main HBase configuration file. This file specifies configuration options which override HBase’s default configuration. You can view (but do not edit) the default configuration file at docs/hbase-default.xml. You can also view the entire effective configuration for your cluster (defaults and overrides) in the HBase Configuration tab of the HBase Web UI.
log4j.properties
Configuration file for HBase logging via log4j.
regionservers
A plain-text file containing a list of hosts which should run a RegionServer in your HBase cluster. By default this file contains the single entry localhost. It should contain a list of hostnames or IP addresses, one per line, and should only contain localhost if each node in your cluster will run a RegionServer on its localhost interface.
dfs.datanode.max.transfer.threads
An HDFS DataNode has an upper bound on the number of files that it will serve at any one time. Before doing any loading, make sure you have configured Hadoop’s conf/hdfs-site.xml, setting the dfs.datanode.max.transfer.threads value to at least the following:
<property>
<name>dfs.datanode.max.transfer.threads</name>
<value>4096</value>
</property>
Be sure to restart your HDFS after making the above configuration.
Not having this configuration in place makes for strange-looking failures. One manifestation is a complaint about missing blocks. For example:
10/12/08 20:10:31 INFO hdfs.DFSClient: Could not obtain block
blk_XXXXXXXXXXXXXXXXXXXXXX_YYYYYYYY from any node: java.io.IOException: No live nodes
contain current block. Will get new block locations from namenode and retry…
Limits on Number of Files and Processes (ulimit)
Apache HBase is a database. It requires the ability to open a large number of files at once. Many Linux distributions limit the number of files a single user is allowed to open to 1024 (or 256 on older versions of OS X). You can check this limit on your servers by running the command ulimit -n when logged in as the user which runs HBase. See the Troubleshooting section for some of the problems you may experience if the limit is too low. You may also notice errors such as the following:
2010-04-06 03:04:37,542 INFO org.apache.hadoop.hdfs.DFSClient: Exception increateBlockOutputStream java.io.EOFException
2010-04-06 03:04:37,542 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning block blk_-6935524980745310745_1391901
It is recommended to raise the ulimit to at least 10,000, but more likely 10,240, because the value is usually expressed in multiples of 1024. Each ColumnFamily has at least one StoreFile, and possibly more than six StoreFiles if the region is under load. The number of open files required depends upon the number of ColumnFamilies and the number of regions. The following is a rough formula for calculating the potential number of open files on a RegionServer.
Calculate the Potential Number of Open Files –
(StoreFiles per ColumnFamily) x (regions per RegionServer)
For example, assuming that a schema had 3 ColumnFamilies per region with an average of 3 StoreFiles per ColumnFamily, and there are 100 regions per RegionServer, the JVM will open 3 * 3 * 100 = 900 file descriptors, not counting open JAR files, configuration files, and others. Opening a file does not take many resources, and the risk of allowing a user to open too many files is minimal.
Another related setting is the number of processes a user is allowed to run at once. In Linux and Unix, the number of processes is set using the ulimit -u command. This should not be confused with the nproc command, which controls the number of CPUs available to a given user. Under load, a ulimit -u that is too low can cause OutOfMemoryError exceptions.
Configuring the maximum number of file descriptors and processes for the user who is running the HBase process is an operating system configuration, rather than an HBase configuration. It is also important to be sure that the settings are changed for the user that actually runs HBase. To see which user started HBase, and that user’s ulimit configuration, look at the first line of the HBase log for that instance.
hbase.tmp.dir
Temporary directory on the local filesystem. Change this setting to point to a location more permanent than ‘/tmp’, the usual resolve for java.io.tmpdir, as the ‘/tmp’ directory is cleared on machine restart.
Default
${java.io.tmpdir}/hbase-${user.name}
hbase.rootdir
The directory shared by region servers and into which HBase persists. The URL should be ‘fully-qualified’ to include the filesystem scheme. For example, to specify the HDFS directory ‘/hbase’ where the HDFS instance’s namenode is running at namenode.example.org on port 9000, set this value to: hdfs://namenode.example.org:9000/hbase. By default, we write to whatever ${hbase.tmp.dir} is set too — usually /tmp — so change this configuration or else all data will be lost on machine restart.
Default ${hbase.tmp.dir}/hbase
hbase.cluster.distributed
The mode the cluster will be in. Possible values are false for standalone mode and true for distributed mode. If false, startup will run all HBase and ZooKeeper daemons together in the one JVM.
Default false
hbase.zookeeper.quorum
Comma separated list of servers in the ZooKeeper ensemble (This config. should have been named hbase.zookeeper.ensemble). For example, “host1.mydomain.com,host2.mydomain.com,host3.mydomain.com”. By default this is set to localhost for local and pseudo-distributed modes of operation. For a fully-distributed setup, this should be set to a full list of ZooKeeper ensemble servers. If HBASE_MANAGES_ZK is set in hbase-env.sh this is the list of servers which hbase will start/stop ZooKeeper on as part of cluster start/stop. Client-side, we will take this list of ensemble members and put it together with the hbase.zookeeper.property.clientPort config. and pass it into zookeeper constructor as the connectString parameter.
Default localhost
zookeeper.recovery.retry.maxsleeptime
Max sleep time before retry zookeeper operations in milliseconds, a max time is needed here so that sleep time won’t grow unboundedly
Default 60000
hbase.local.dir
Directory on the local filesystem to be used as a local storage.
Default ${hbase.tmp.dir}/local/
hbase.master.port
The port the HBase Master should bind to.
Default 16000
hbase.master.info.port
The port for the HBase Master web UI. Set to -1 if you do not want a UI instance run.
Default 16010
hbase.master.info.bindAddress
The bind address for the HBase Master web UI
Default 0.0.0.0
hbase.master.logcleaner.plugins
A comma-separated list of BaseLogCleanerDelegate invoked by the LogsCleaner service. These WAL cleaners are called in order, so put the cleaner that prunes the most files in front. To implement your own BaseLogCleanerDelegate, just put it in HBase’s classpath and add the fully qualified class name here. Always add the above default log cleaners in the list.
Default org.apache.hadoop.hbase.master.cleaner.TimeToLiveLogCleaner,org.apache.hadoop.hbase.master.cleaner.TimeToLiveProcedureWALCleaner
hbase.master.logcleaner.ttl
How long a WAL remain in the archive ({hbase.rootdir}/oldWALs) directory, after which it will be cleaned by a Master thread. The value is in milliseconds.
Default 600000
hbase.master.procedurewalcleaner.ttl
How long a Procedure WAL will remain in the archive directory, after which it will be cleaned by a Master thread. The value is in milliseconds.
Default 604800000
hbase.master.hfilecleaner.plugins
A comma-separated list of BaseHFileCleanerDelegate invoked by the HFileCleaner service. These HFiles cleaners are called in order, so put the cleaner that prunes the most files in front. To implement your own BaseHFileCleanerDelegate, just put it in HBase’s classpath and add the fully qualified class name here. Always add the above default log cleaners in the list as they will be overwritten in hbase-site.xml.
Default org.apache.hadoop.hbase.master.cleaner.TimeToLiveHFileCleaner
hbase.master.infoserver.redirect
Whether or not the Master listens to the Master web UI port (hbase.master.info.port) and redirects requests to the web UI server shared by the Master and RegionServer. Config. makes sense when Master is serving Regions (not the default).
Default true
hbase.master.fileSplitTimeout
Splitting a region, how long to wait on the file-splitting step before aborting the attempt. Default: 600000. This setting used to be known as hbase.regionserver.fileSplitTimeout in hbase-1.x. Split is now run master-side hence the rename (If a ‘hbase.master.fileSplitTimeout’ setting found, will use it to prime the current ‘hbase.master.fileSplitTimeout’ Configuration.
Default 600000
hbase.regionserver.port
The port the HBase RegionServer binds to.
Default 16020
hbase.regionserver.info.port
The port for the HBase RegionServer web UI Set to -1 if you do not want the RegionServer UI to run.
Default 16030
hbase.regionserver.info.bindAddress
The address for the HBase RegionServer web UI
Default 0.0.0.0
hbase.regionserver.info.port.auto
Whether or not the Master or RegionServer UI should search for a port to bind to. Enables automatic port search if hbase.regionserver.info.port is already in use. Useful for testing, turned off by default.
Default false
hbase.regionserver.handler.count
Count of RPC Listener instances spun up on RegionServers. Same property is used by the Master for count of master handlers. Too many handlers can be counter-productive. Make it a multiple of CPU count. If mostly read-only, handlers count close to cpu count does well. Start with twice the CPU count and tune from there.
Default 30
hbase.ipc.server.callqueue.handler.factor
Factor to determine the number of call queues. A value of 0 means a single queue shared between all the handlers. A value of 1 means that each handler has its own queue.
Default 0.1
hbase.ipc.server.callqueue.read.ratio
Split the call queues into read and write queues. The specified interval (which should be between 0.0 and 1.0) will be multiplied by the number of call queues. A value of 0 indicate to not split the call queues, meaning that both read and write requests will be pushed to the same set of queues. A value lower than 0.5 means that there will be less read queues than write queues. A value of 0.5 means there will be the same number of read and write queues. A value greater than 0.5 means that there will be more read queues than write queues. A value of 1.0 means that all the queues except one are used to dispatch read requests. Example: Given the total number of call queues being 10 a read.ratio of 0 means that: the 10 queues will contain both read/write requests. a read.ratio of 0.3 means that: 3 queues will contain only read requests and 7 queues will contain only write requests. a read.ratio of 0.5 means that: 5 queues will contain only read requests and 5 queues will contain only write requests. a read.ratio of 0.8 means that: 8 queues will contain only read requests and 2 queues will contain only write requests. a read.ratio of 1 means that: 9 queues will contain only read requests and 1 queues will contain only write requests.
Default 0
hbase.ipc.server.callqueue.scan.ratio
Given the number of read call queues, calculated from the total number of call queues multiplied by the callqueue.read.ratio, the scan.ratio property will split the read call queues into small-read and long-read queues. A value lower than 0.5 means that there will be less long-read queues than short-read queues. A value of 0.5 means that there will be the same number of short-read and long-read queues. A value greater than 0.5 means that there will be more long-read queues than short-read queues A value of 0 or 1 indicate to use the same set of queues for gets and scans. Example: Given the total number of read call queues being 8 a scan.ratio of 0 or 1 means that: 8 queues will contain both long and short read requests. a scan.ratio of 0.3 means that: 2 queues will contain only long-read requests and 6 queues will contain only short-read requests. a scan.ratio of 0.5 means that: 4 queues will contain only long-read requests and 4 queues will contain only short-read requests. a scan.ratio of 0.8 means that: 6 queues will contain only long-read requests and 2 queues will contain only short-read requests.
Default 0
hbase.regionserver.msginterval
Interval between messages from the RegionServer to Master in milliseconds.
Default 3000
hbase.regionserver.logroll.period
Period at which we will roll the commit log regardless of how many edits it has.
Default 3600000
hbase.regionserver.logroll.errors.tolerated
The number of consecutive WAL close errors we will allow before triggering a server abort. A setting of 0 will cause the region server to abort if closing the current WAL writer fails during log rolling. Even a small value (2 or 3) will allow a region server to ride over transient HDFS errors.
Default 2
hbase.regionserver.hlog.reader.impl
The WAL file reader implementation.
Default org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader
hbase.regionserver.hlog.writer.impl
The WAL file writer implementation.
Default org.apache.hadoop.hbase.regionserver.wal.ProtobufLogWriter
hbase.regionserver.global.memstore.size
Maximum size of all memstores in a region server before new updates are blocked and flushes are forced. Defaults to 40% of heap (0.4). Updates are blocked and flushes are forced until size of all memstores in a region server hits hbase.regionserver.global.memstore.size.lower.limit. The default value in this configuration has been intentionally left empty in order to honor the old hbase.regionserver.global.memstore.upperLimit property if present.
Default none
hbase.regionserver.global.memstore.size.lower.limit
Maximum size of all memstores in a region server before flushes are forced. Defaults to 95% of hbase.regionserver.global.memstore.size (0.95). A 100% value for this value causes the minimum possible flushing to occur when updates are blocked due to memstore limiting. The default value in this configuration has been intentionally left empty in order to honor the old hbase.regionserver.global.memstore.lowerLimit property if present.
Default none
hbase.systemtables.compacting.memstore.type
Determines the type of memstore to be used for system tables like META, namespace tables etc. By default NONE is the type and hence we use the default memstore for all the system tables. If we need to use compacting memstore for system tables then set this property to BASIC/EAGER
Default NONE
hbase.regionserver.optionalcacheflushinterval
Maximum amount of time an edit lives in memory before being automatically flushed. Default 1 hour. Set it to 0 to disable automatic flushing.
Default 3600000
hbase.regionserver.dns.interface
The name of the Network Interface from which a region server should report its IP address.
DefaultDefaulthbase.regionserver.dns.nameserver
The host name or IP address of the name server (DNS) which a region server should use to determine the host name used by the master for communication and display purposes.
DefaultDefaulthbase.regionserver.region.split.policy
A split policy determines when a region should be split. The various other split policies that are available currently are BusyRegionSplitPolicy, ConstantSizeRegionSplitPolicy, DisabledRegionSplitPolicy, DelimitedKeyPrefixRegionSplitPolicy, KeyPrefixRegionSplitPolicy, and SteppingSplitPolicy. DisabledRegionSplitPolicy blocks manual region splitting.
Default org.apache.hadoop.hbase.regionserver.SteppingSplitPolicy
hbase.regionserver.regionSplitLimit
Limit for the number of regions after which no more region splitting should take place. This is not hard limit for the number of regions but acts as a guideline for the regionserver to stop splitting after a certain limit. Default is set to 1000.
Default 1000
zookeeper.session.timeout
ZooKeeper session timeout in milliseconds. It is used in two different ways. First, this value is used in the ZK client that HBase uses to connect to the ensemble. It is also used by HBase when it starts a ZK server and it is passed as the ‘maxSessionTimeout’. See http://hadoop.apache.org/zookeeper/docs/current/zookeeperProgrammers.html#ch_zkSessions. For example, if an HBase region server connects to a ZK ensemble that’s also managed by HBase, then the session timeout will be the one specified by this configuration. But, a region server that connects to an ensemble managed with a different configuration will be subjected that ensemble’s maxSessionTimeout. So, even though HBase might propose using 90 seconds, the ensemble can have a max timeout lower than this and it will take precedence. The current default that ZK ships with is 40 seconds, which is lower than HBase’s.
Default 90000
zookeeper.znode.parent
Root ZNode for HBase in ZooKeeper. All of HBase’s ZooKeeper files that are configured with a relative path will go under this node. By default, all of HBase’s ZooKeeper file paths are configured with a relative path, so they will all go under this directory unless changed.
Default /hbase
zookeeper.znode.acl.parent
Root ZNode for access control lists.
Default acl
hbase.zookeeper.dns.interface
The name of the Network Interface from which a ZooKeeper server should report its IP address.
DefaultDefaulthbase.zookeeper.dns.nameserver
The host name or IP address of the name server (DNS) which a ZooKeeper server should use to determine the host name used by the master for communication and display purposes.
DefaultDefaulthbase.zookeeper.peerport
Port used by ZooKeeper peers to talk to each other. See http://hadoop.apache.org/zookeeper/docs/r3.1.1/zookeeperStarted.html#sc_RunningReplicatedZooKeeper for more information.
Default 2888
hbase.zookeeper.leaderport
Port used by ZooKeeper for leader election. See http://hadoop.apache.org/zookeeper/docs/r3.1.1/zookeeperStarted.html#sc_RunningReplicatedZooKeeper for more information.
Default 3888
hbase.zookeeper.property.initLimit
Property from ZooKeeper’s config zoo.cfg. The number of ticks that the initial synchronization phase can take.
Default 10
hbase.zookeeper.property.syncLimit
Property from ZooKeeper’s config zoo.cfg. The number of ticks that can pass between sending a request and getting an acknowledgment.
Default 5
hbase.zookeeper.property.dataDir
Property from ZooKeeper’s config zoo.cfg. The directory where the snapshot is stored.
Default ${hbase.tmp.dir}/zookeeper
hbase.zookeeper.property.clientPort
Property from ZooKeeper’s config zoo.cfg. The port at which the clients will connect.
Default 2181
hbase.zookeeper.property.maxClientCnxns
Property from ZooKeeper’s config zoo.cfg. Limit on number of concurrent connections (at the socket level) that a single client, identified by IP address, may make to a single member of the ZooKeeper ensemble. Set high to avoid zk connection issues running standalone and pseudo-distributed.
Default 300
hbase.client.write.buffer
Default size of the BufferedMutator write buffer in bytes. A bigger buffer takes more memory — on both the client and server side since server instantiates the passed write buffer to process it — but a larger buffer size reduces the number of RPCs made. For an estimate of server-side memory-used, evaluate hbase.client.write.buffer * hbase.regionserver.handler.count
Default 2097152
hbase.client.pause
General client pause value. Used mostly as value to wait before running a retry of a failed get, region lookup, etc. See hbase.client.retries.number for description of how we backoff from this initial pause amount and how this pause works w/ retries.
Default 100
hbase.client.pause.cqtbe
Whether or not to use a special client pause for CallQueueTooBigException (cqtbe). Set this property to a higher value than hbase.client.pause if you observe frequent CQTBE from the same RegionServer and the call queue there keeps full
Default none
hbase.client.retries.number
Maximum retries. Used as maximum for all retryable operations such as the getting of a cell’s value, starting a row update, etc. Retry interval is a rough function based on hbase.client.pause. At first we retry at this interval but then with backoff, we pretty quickly reach retrying every ten seconds. See HConstants#RETRY_BACKOFF for how the backup ramps up. Change this setting and hbase.client.pause to suit your workload.
Default 15
hbase.client.max.total.tasks
The maximum number of concurrent mutation tasks a single HTable instance will send to the cluster.
Default 100
hbase.client.max.perserver.tasks
The maximum number of concurrent mutation tasks a single HTable instance will send to a single region server.
Default 2
hbase.client.max.perregion.tasks
The maximum number of concurrent mutation tasks the client will maintain to a single Region. That is, if there is already hbase.client.max.perregion.tasks writes in progress for this region, new puts won’t be sent to this region until some writes finishes.
Default 1
hbase.client.perserver.requests.threshold
The max number of concurrent pending requests for one server in all client threads (process level). Exceeding requests will be thrown ServerTooBusyException immediately to prevent user’s threads being occupied and blocked by only one slow region server. If you use a fix number of threads to access HBase in a synchronous way, set this to a suitable value which is related to the number of threads will help you. See https://issues.apache.org/jira/browse/HBASE-16388 for details.
Default 2147483647
hbase.client.scanner.caching
Number of rows that we try to fetch when calling next on a scanner if it is not served from (local, client) memory. This configuration works together with hbase.client.scanner.max.result.size to try and use the network efficiently. The default value is Integer.MAX_VALUE by default so that the network will fill the chunk size defined by hbase.client.scanner.max.result.size rather than be limited by a particular number of rows since the size of rows varies table to table. If you know ahead of time that you will not require more than a certain number of rows from a scan, this configuration should be set to that row limit via Scan#setCaching. Higher caching values will enable faster scanners but will eat up more memory and some calls of next may take longer and longer times when the cache is empty. Do not set this value such that the time between invocations is greater than the scanner timeout; i.e. hbase.client.scanner.timeout.period
Default 2147483647
hbase.client.keyvalue.maxsize
Specifies the combined maximum allowed size of a KeyValue instance. This is to set an upper boundary for a single entry saved in a storage file. Since they cannot be split it helps avoiding that a region cannot be split any further because the data is too large. It seems wise to set this to a fraction of the maximum region size. Setting it to zero or less disables the check.
Default 10485760
hbase.server.keyvalue.maxsize
Maximum allowed size of an individual cell, inclusive of value and all key components. A value of 0 or less disables the check. The default value is 10MB. This is a safety setting to protect the server from OOM situations.
Default 10485760
hbase.client.scanner.timeout.period
Client scanner lease period in milliseconds.
Default 60000
hbase.client.localityCheck.threadPoolSize
Default 2
hbase.bulkload.retries.number
Maximum retries. This is maximum number of iterations to atomic bulk loads are attempted in the face of splitting operations 0 means never give up.
Default 10
hbase.master.balancer.maxRitPercent
The max percent of regions in transition when balancing. The default value is 1.0. So there are no balancer throttling. If set this config to 0.01, It means that there are at most 1% regions in transition when balancing. Then the cluster’s availability is at least 99% when balancing.
Default 1.0
hbase.balancer.period
Period at which the region balancer runs in the Master.
Default 300000
hbase.normalizer.period
Period at which the region normalizer runs in the Master.
Default 300000
hbase.normalizer.min.region.count
configure the minimum number of regions
Default 3
hbase.regions.slop
Rebalance if any regionserver has average + (average * slop) regions. The default value of this parameter is 0.001 in StochasticLoadBalancer (the default load balancer), while the default is 0.2 in other load balancers (i.e., SimpleLoadBalancer).
Default 0.001
hbase.server.thread.wakefrequency
Time to sleep in between searches for work (in milliseconds). Used as sleep interval by service threads such as log roller.
Default 10000
hbase.server.versionfile.writeattempts
How many times to retry attempting to write a version file before just aborting. Each attempt is separated by the hbase.server.thread.wakefrequency milliseconds.
Default 3
hbase.hregion.memstore.flush.size
Memstore will be flushed to disk if size of the memstore exceeds this number of bytes. Value is checked by a thread that runs every hbase.server.thread.wakefrequency.
Default 134217728
hbase.hregion.percolumnfamilyflush.size.lower.bound.min
If FlushLargeStoresPolicy is used and there are multiple column families, then every time that we hit the total memstore limit, we find out all the column families whose memstores exceed a “lower bound” and only flush them while retaining the others in memory. The “lower bound” will be “hbase.hregion.memstore.flush.size / column_family_number” by default unless value of this property is larger than that. If none of the families have their memstore size more than lower bound, all the memstores will be flushed (just as usual).
Default 16777216
hbase.hregion.preclose.flush.size
If the memstores in a region are this size or larger when we go to close, run a “pre-flush” to clear out memstores before we put up the region closed flag and take the region offline. On close, a flush is run under the close flag to empty memory. During this time the region is offline and we are not taking on any writes. If the memstore content is large, this flush could take a long time to complete. The preflush is meant to clean out the bulk of the memstore before putting up the close flag and taking the region offline so the flush that runs under the close flag has little to do.
Default 5242880
hbase.hregion.memstore.block.multiplier
Block updates if memstore has hbase.hregion.memstore.block.multiplier times hbase.hregion.memstore.flush.size bytes. Useful preventing runaway memstore during spikes in update traffic. Without an upper-bound, memstore fills such that when it flushes the resultant flush files take a long time to compact or split, or worse, we OOME.
Default 4
hbase.hregion.memstore.mslab.enabled
Enables the MemStore-Local Allocation Buffer, a feature which works to prevent heap fragmentation under heavy write loads. This can reduce the frequency of stop-the-world GC pauses on large heaps.
Default true
hbase.hregion.max.filesize
Maximum HFile size. If the sum of the sizes of a region’s HFiles has grown to exceed this value, the region is split in two.
Default 10737418240
hbase.hregion.majorcompaction
Time between major compactions, expressed in milliseconds. Set to 0 to disable time-based automatic major compactions. User-requested and size-based major compactions will still run. This value is multiplied by hbase.hregion.majorcompaction.jitter to cause compaction to start at a somewhat-random time during a given window of time. The default value is 7 days, expressed in milliseconds. If major compactions are causing disruption in your environment, you can configure them to run at off-peak times for your deployment, or disable time-based major compactions by setting this parameter to 0, and run major compactions in a cron job or by another external mechanism.
Default 604800000
hbase.hregion.majorcompaction.jitter
A multiplier applied to hbase.hregion.majorcompaction to cause compaction to occur a given amount of time either side of hbase.hregion.majorcompaction. The smaller the number, the closer the compactions will happen to the hbase.hregion.majorcompaction interval.
Default 0.50
hbase.hstore.compactionThreshold
If more than this number of StoreFiles exist in any one Store (one StoreFile is written per flush of MemStore), a compaction is run to rewrite all StoreFiles into a single StoreFile. Larger values delay compaction, but when compaction does occur, it takes longer to complete.
Default 3
hbase.regionserver.compaction.enabled
Enable/disable compactions on by setting true/false. We can further switch compactions dynamically with the compaction_switch shell command.
Default true
hbase.hstore.flusher.count
The number of flush threads. With fewer threads, the MemStore flushes will be queued. With more threads, the flushes will be executed in parallel, increasing the load on HDFS, and potentially causing more compactions.
Default 2
hbase.hstore.blockingStoreFiles
If more than this number of StoreFiles exist in any one Store (one StoreFile is written per flush of MemStore), updates are blocked for this region until a compaction is completed, or until hbase.hstore.blockingWaitTime has been exceeded.
Default 16
hbase.hstore.blockingWaitTime
The time for which a region will block updates after reaching the StoreFile limit defined by hbase.hstore.blockingStoreFiles. After this time has elapsed, the region will stop blocking updates even if a compaction has not been completed.
Default 90000
hbase.hstore.compaction.min
The minimum number of StoreFiles which must be eligible for compaction before compaction can run. The goal of tuning hbase.hstore.compaction.min is to avoid ending up with too many tiny StoreFiles to compact. Setting this value to 2 would cause a minor compaction each time you have two StoreFiles in a Store, and this is probably not appropriate. If you set this value too high, all the other values will need to be adjusted accordingly. For most cases, the default value is appropriate. In previous versions of HBase, the parameter hbase.hstore.compaction.min was named hbase.hstore.compactionThreshold.
Default 3
hbase.hstore.compaction.max
The maximum number of StoreFiles which will be selected for a single minor compaction, regardless of the number of eligible StoreFiles. Effectively, the value of hbase.hstore.compaction.max controls the length of time it takes a single compaction to complete. Setting it larger means that more StoreFiles are included in a compaction. For most cases, the default value is appropriate.
Default 10
hbase.hstore.compaction.min.size
A StoreFile (or a selection of StoreFiles, when using ExploringCompactionPolicy) smaller than this size will always be eligible for minor compaction. HFiles this size or larger are evaluated by hbase.hstore.compaction.ratio to determine if they are eligible. Because this limit represents the “automatic include” limit for all StoreFiles smaller than this value, this value may need to be reduced in write-heavy environments where many StoreFiles in the 1-2 MB range are being flushed, because every StoreFile will be targeted for compaction and the resulting StoreFiles may still be under the minimum size and require further compaction. If this parameter is lowered, the ratio check is triggered more quickly. This addressed some issues seen in earlier versions of HBase but changing this parameter is no longer necessary in most situations. Default: 128 MB expressed in bytes.
Default 134217728
hbase.hstore.compaction.max.size
A StoreFile (or a selection of StoreFiles, when using ExploringCompactionPolicy) larger than this size will be excluded from compaction. The effect of raising hbase.hstore.compaction.max.size is fewer, larger StoreFiles that do not get compacted often. If you feel that compaction is happening too often without much benefit, you can try raising this value. Default: the value of LONG.MAX_VALUE, expressed in bytes.
Default 9223372036854775807
hbase.hstore.compaction.ratio
For minor compaction, this ratio is used to determine whether a given StoreFile which is larger than hbase.hstore.compaction.min.size is eligible for compaction. Its effect is to limit compaction of large StoreFiles. The value of hbase.hstore.compaction.ratio is expressed as a floating-point decimal. A large ratio, such as 10, will produce a single giant StoreFile. Conversely, a low value, such as .25, will produce behavior similar to the BigTable compaction algorithm, producing four StoreFiles. A moderate value of between 1.0 and 1.4 is recommended. When tuning this value, you are balancing write costs with read costs. Raising the value (to something like 1.4) will have more write costs, because you will compact larger StoreFiles. However, during reads, HBase will need to seek through fewer StoreFiles to accomplish the read. Consider this approach if you cannot take advantage of Bloom filters. Otherwise, you can lower this value to something like 1.0 to reduce the background cost of writes, and use Bloom filters to control the number of StoreFiles touched during reads. For most cases, the default value is appropriate.
Default 1.2F
hbase.hstore.compaction.ratio.offpeak
Allows you to set a different (by default, more aggressive) ratio for determining whether larger StoreFiles are included in compactions during off-peak hours. Works in the same way as hbase.hstore.compaction.ratio. Only applies if hbase.offpeak.start.hour and hbase.offpeak.end.hour are also enabled.
Default 5.0F
hbase.hstore.time.to.purge.deletes
The amount of time to delay purging of delete markers with future timestamps. If unset, or set to 0, all delete markers, including those with future timestamps, are purged during the next major compaction. Otherwise, a delete marker is kept until the major compaction which occurs after the marker’s timestamp plus the value of this setting, in milliseconds.
Default 0
hbase.offpeak.start.hour
The start of off-peak hours, expressed as an integer between 0 and 23, inclusive. Set to -1 to disable off-peak.
Default -1
hbase.offpeak.end.hour
The end of off-peak hours, expressed as an integer between 0 and 23, inclusive. Set to -1 to disable off-peak.
Default -1
hbase.regionserver.thread.compaction.throttle
There are two different thread pools for compactions, one for large compactions and the other for small compactions. This helps to keep compaction of lean tables (such as hbase:meta) fast. If a compaction is larger than this threshold, it goes into the large compaction pool. In most cases, the default value is appropriate. Default: 2 x hbase.hstore.compaction.max x hbase.hregion.memstore.flush.size (which defaults to 128MB). The value field assumes that the value of hbase.hregion.memstore.flush.size is unchanged from the default.
Default 2684354560
hbase.regionserver.majorcompaction.pagecache.drop
Specifies whether to drop pages read/written into the system page cache by major compactions. Setting it to true helps prevent major compactions from polluting the page cache, which is almost always required, especially for clusters with low/moderate memory to storage ratio.
Default true
hbase.regionserver.minorcompaction.pagecache.drop
Specifies whether to drop pages read/written into the system page cache by minor compactions. Setting it to true helps prevent minor compactions from polluting the page cache, which is most beneficial on clusters with low memory to storage ratio or very write heavy clusters. You may want to set it to false under moderate to low write workload when bulk of the reads are on the most recently written data.
Default true
hbase.hstore.compaction.kv.max
The maximum number of KeyValues to read and then write in a batch when flushing or compacting. Set this lower if you have big KeyValues and problems with Out Of Memory Exceptions Set this higher if you have wide, small rows.
Default 10
hbase.storescanner.parallel.seek.enable
Enables StoreFileScanner parallel-seeking in StoreScanner, a feature which can reduce response latency under special conditions.
Default false
hbase.storescanner.parallel.seek.threads
The default thread pool size if parallel-seeking feature enabled.
Default 10
hfile.block.cache.size
Percentage of maximum heap (-Xmx setting) to allocate to block cache used by a StoreFile. Default of 0.4 means allocate 40%. Set to 0 to disable but it’s not recommended; you need at least enough cache to hold the storefile indices.
Default 0.4
hfile.block.index.cacheonwrite
This allows to put non-root multi-level index blocks into the block cache at the time the index is being written.
Default false
hfile.index.block.max.size
When the size of a leaf-level, intermediate-level, or root-level index block in a multi-level block index grows to this size, the block is written out and a new block is started.
Default 131072
hbase.bucketcache.ioengine
Where to store the contents of the bucketcache. One of: offheap, file, files or mmap. If a file or files, set it to file(s):PATH_TO_FILE. mmap means the content will be in an mmaped file. Use mmap:PATH_TO_FILE. See http://hbase.apache.org/book.html#offheap.blockcache for more information.
Default none
hbase.bucketcache.size
A float that EITHER represents a percentage of total heap memory size to give to the cache (if < 1.0) OR, it is the total capacity in megabytes of BucketCache. Default: 0.0
Default none
hbase.bucketcache.bucket.sizes
A comma-separated list of sizes for buckets for the bucketcache. Can be multiple sizes. List block sizes in order from smallest to largest. The sizes you use will depend on your data access patterns. Must be a multiple of 256 else you will run into ‘java.io.IOException: Invalid HFile block magic’ when you go to read from cache. If you specify no values here, then you pick up the default bucketsizes set in code (See BucketAllocator#DEFAULT_BUCKET_SIZES).
Default none
hfile.format.version
The HFile format version to use for new files. Version 3 adds support for tags in hfiles (See http://hbase.apache.org/book.html#hbase.tags). Also see the configuration ‘hbase.replication.rpc.codec’.
Default 3
hfile.block.bloom.cacheonwrite
Enables cache-on-write for inline blocks of a compound Bloom filter.
Default false
io.storefile.bloom.block.size
The size in bytes of a single block (“chunk”) of a compound Bloom filter. This size is approximate, because Bloom blocks can only be inserted at data block boundaries, and the number of keys per data block varies.
Default 131072
hbase.rs.cacheblocksonwrite
Whether an HFile block should be added to the block cache when the block is finished.
Default false
hbase.rpc.timeout
This is for the RPC layer to define how long (millisecond) HBase client applications take for a remote call to time out. It uses pings to check connections but will eventually throw a TimeoutException.
Default 60000
hbase.client.operation.timeout
Operation timeout is a top-level restriction (millisecond) that makes sure a blocking operation in Table will not be blocked more than this. In each operation, if rpc request fails because of timeout or other reason, it will retry until success or throw RetriesExhaustedException. But if the total time being blocking reach the operation timeout before retries exhausted, it will break early and throw SocketTimeoutException.
Default 1200000
hbase.cells.scanned.per.heartbeat.check
The number of cells scanned in between heartbeat checks. Heartbeat checks occur during the processing of scans to determine whether or not the server should stop scanning in order to send back a heartbeat message to the client. Heartbeat messages are used to keep the client-server connection alive during long running scans. Small values mean that the heartbeat checks will occur more often and thus will provide a tighter bound on the execution time of the scan. Larger values mean that the heartbeat checks occur less frequently
Default 10000
hbase.rpc.shortoperation.timeout
This is another version of “hbase.rpc.timeout”. For those RPC operation within cluster, we rely on this configuration to set a short timeout limitation for short operation. For example, short rpc timeout for region server’s trying to report to active master can benefit quicker master failover process.
Default 10000
hbase.ipc.client.tcpnodelay
Set no delay on rpc socket connections. Default true
hbase.regionserver.hostname
This config is for experts: don’t set its value unless you really know what you are doing. When set to a non-empty value, this represents the (external facing) hostname for the underlying server. See https://issues.apache.org/jira/browse/HBASE-12954 for details.
Default none
hbase.regionserver.hostname.disable.master.reversedns
This config is for experts: don’t set its value unless you really know what you are doing. When set to true, regionserver will use the current node hostname for the servername and HMaster will skip reverse DNS lookup and use the hostname sent by regionserver instead. Note that this config and hbase.regionserver.hostname are mutually exclusive. See https://issues.apache.org/jira/browse/HBASE-18226 for more details.
Default false
hbase.master.keytab.file
Full path to the kerberos keytab file to use for logging in the configured HMaster server principal.
Default none
hbase.master.kerberos.principal
Ex. “hbase/[email protected]”. The kerberos principal name that should be used to run the HMaster process. The principal name should be in the form: user/hostname@DOMAIN. If “_HOST” is used as the hostname portion, it will be replaced with the actual hostname of the running instance.
Default none
hbase.regionserver.keytab.file
Full path to the kerberos keytab file to use for logging in the configured HRegionServer server principal.
Default none
hbase.regionserver.kerberos.principal
Ex. “hbase/[email protected]”. The kerberos principal name that should be used to run the HRegionServer process. The principal name should be in the form: user/hostname@DOMAIN. If “_HOST” is used as the hostname portion, it will be replaced with the actual hostname of the running instance. An entry for this principal must exist in the file specified in hbase.regionserver.keytab.file
Default none
hadoop.policy.file
The policy configuration file used by RPC servers to make authorization decisions on client requests. Only used when HBase security is enabled.
Default hbase-policy.xml
hbase.superuser
List of users or groups (comma-separated), who are allowed full privileges, regardless of stored ACLs, across the cluster. Only used when HBase security is enabled.
Default none
hbase.auth.key.update.interval
The update interval for master key for authentication tokens in servers in milliseconds. Only used when HBase security is enabled.
Default 86400000
hbase.auth.token.max.lifetime
The maximum lifetime in milliseconds after which an authentication token expires. Only used when HBase security is enabled.
Default 604800000
hbase.ipc.client.fallback-to-simple-auth-allowed
When a client is configured to attempt a secure connection, but attempts to connect to an insecure server, that server may instruct the client to switch to SASL SIMPLE (unsecure) authentication. This setting controls whether or not the client will accept this instruction from the server. When false (the default), the client will not allow the fallback to SIMPLE authentication, and will abort the connection.
Default false
hbase.ipc.server.fallback-to-simple-auth-allowed
When a server is configured to require secure connections, it will reject connection attempts from clients using SASL SIMPLE (unsecure) authentication. This setting allows secure servers to accept SASL SIMPLE connections from clients when the client requests. When false (the default), the server will not allow the fallback to SIMPLE authentication, and will reject the connection. WARNING: This setting should ONLY be used as a temporary measure while converting clients over to secure authentication. It MUST BE DISABLED for secure operation.
Default false
hbase.display.keys
When this is set to true the webUI and such will display all start/end keys as part of the table details, region names, etc. When this is set to false, the keys are hidden.
Default true
hbase.coprocessor.enabled
Enables or disables coprocessor loading. If ‘false’ (disabled), any other coprocessor related configuration will be ignored.
Default true
hbase.coprocessor.user.enabled
Enables or disables user (aka. table) coprocessor loading. If ‘false’ (disabled), any table coprocessor attributes in table descriptors will be ignored. If “hbase.coprocessor.enabled” is ‘false’ this setting has no effect.
Default true
hbase.coprocessor.region.classes
A comma-separated list of region observer or endpoint coprocessors that are loaded by default on all tables. For any override coprocessor method, these classes will be called in order. After implementing your own Coprocessor, add it to HBase’s classpath and add the fully qualified class name here. A coprocessor can also be loaded on demand by setting HTableDescriptor or the HBase shell.
Default none
hbase.coprocessor.master.classes
A comma-separated list of org.apache.hadoop.hbase.coprocessor.MasterObserver coprocessors that are loaded by default on the active HMaster process. For any implemented coprocessor methods, the listed classes will be called in order. After implementing your own MasterObserver, just put it in HBase’s classpath and add the fully qualified class name here.
Default none
hbase.coprocessor.abortonerror
Set to true to cause the hosting server (master or regionserver) to abort if a coprocessor fails to load, fails to initialize, or throws an unexpected Throwable object. Setting this to false will allow the server to continue execution but the system wide state of the coprocessor in question will become inconsistent as it will be properly executing in only a subset of servers, so this is most useful for debugging only.
Default true
hbase.rest.port
The port for the HBase REST server.
Default 8080
hbase.rest.readonly
Defines the mode the REST server will be started in. Possible values are: false: All HTTP methods are permitted – GET/PUT/POST/DELETE. true: Only the GET method is permitted.
Default false
hbase.rest.threads.max
The maximum number of threads of the REST server thread pool. Threads in the pool are reused to process REST requests. This controls the maximum number of requests processed concurrently. It may help to control the memory used by the REST server to avoid OOM issues. If the thread pool is full, incoming requests will be queued up and wait for some free threads.
Default 100
hbase.rest.threads.min
The minimum number of threads of the REST server thread pool. The thread pool always has at least these number of threads so the REST server is ready to serve incoming requests.
Default 2
hbase.rest.support.proxyuser
Enables running the REST server to support proxy-user mode.
Default false
hbase.defaults.for.version.skip
Set to true to skip the ‘hbase.defaults.for.version’ check. Setting this to true can be useful in contexts other than the other side of a maven generation; i.e. running in an IDE. You’ll want to set this boolean to true to avoid seeing the RuntimeException complaint: “hbase-default.xml file seems to be for and old version of HBase (\${hbase.version}), this version is X.X.X-SNAPSHOT”
Default false
hbase.table.lock.enable
Set to true to enable locking the table in zookeeper for schema change operations. Table locking from master prevents concurrent schema modifications to corrupt table state.
Default true
hbase.table.max.rowsize
Maximum size of single row in bytes (default is 1 Gb) for Get’ting or Scan’ning without in-row scan flag set. If row size exceeds this limit RowTooBigException is thrown to client.
Default 1073741824
hbase.thrift.minWorkerThreads
The “core size” of the thread pool. New threads are created on every connection until this many threads are created.
Default 16
hbase.thrift.maxWorkerThreads
The maximum size of the thread pool. When the pending request queue overflows, new threads are created until their number reaches this number. After that, the server starts dropping connections.
Default 1000
hbase.thrift.maxQueuedRequests
The maximum number of pending Thrift connections waiting in the queue. If there are no idle threads in the pool, the server queues requests. Only when the queue overflows, new threads are added, up to hbase.thrift.maxQueuedRequests threads.
Default 1000
hbase.regionserver.thrift.framed
Use Thrift TFramedTransport on the server side. This is the recommended transport for thrift servers and requires a similar setting on the client side. Changing this to false will select the default transport, vulnerable to DoS when malformed requests are issued due to THRIFT-601.
Default false
hbase.regionserver.thrift.framed.max_frame_size_in_mb
Default frame size when using framed transport, in MB
Default 2
hbase.regionserver.thrift.compact
Use Thrift TCompactProtocol binary serialization protocol.
Default false
hbase.rootdir.perms
FS Permissions for the root data subdirectory in a secure (kerberos) setup. When master starts, it creates the rootdir with this permissions or sets the permissions if it does not match.
Default 700
hbase.wal.dir.perms
FS Permissions for the root WAL directory in a secure(kerberos) setup. When master starts, it creates the WAL dir with this permissions or sets the permissions if it does not match.
Default 700
hbase.data.umask.enable
Enable, if true, that file permissions should be assigned to the files written by the regionserver
Default false
hbase.data.umask
File permissions that should be used to write data files when hbase.data.umask.enable is true
Default 000
hbase.snapshot.enabled
Set to true to allow snapshots to be taken / restored / cloned.
Default true
hbase.snapshot.restore.take.failsafe.snapshot
Set to true to take a snapshot before the restore operation. The snapshot taken will be used in case of failure, to restore the previous state. At the end of the restore operation this snapshot will be deleted
Default true
hbase.snapshot.restore.failsafe.name
Name of the failsafe snapshot taken by the restore operation. You can use the {snapshot.name}, {table.name} and {restore.timestamp} variables to create a name based on what you are restoring.
Default hbase-failsafe-{snapshot.name}-{restore.timestamp}
hbase.snapshot.working.dir
Location where the snapshotting process will occur. The location of the completed snapshots will not change, but the temporary directory where the snapshot process occurs will be set to this location. This can be a separate filesystem than the root directory, for performance increase purposes. See HBASE-21098 for more information
Default none
hbase.server.compactchecker.interval.multiplier
The number that determines how often we scan to see if compaction is necessary. Normally, compactions are done after some events (such as memstore flush), but if region didn’t receive a lot of writes for some time, or due to different compaction policies, it may be necessary to check it periodically. The interval between checks is hbase.server.compactchecker.interval.multiplier multiplied by hbase.server.thread.wakefrequency.
Default 1000
hbase.lease.recovery.timeout
How long we wait on dfs lease recovery in total before giving up.
Default 900000
hbase.lease.recovery.dfs.timeout
How long between dfs recover lease invocations. Should be larger than the sum of the time it takes for the namenode to issue a block recovery command as part of datanode; dfs.heartbeat.interval and the time it takes for the primary datanode, performing block recovery to timeout on a dead datanode; usually dfs.client.socket-timeout. See the end of HBASE-8389 for more.
Default 64000
hbase.column.max.version
New column family descriptors will use this value as the default number of versions to keep.
Default 1
dfs.client.read.shortcircuit
If set to true, this configuration parameter enables short-circuit local reads.
Default false
dfs.domain.socket.path
This is a path to a UNIX domain socket that will be used for communication between the DataNode and local HDFS clients, if dfs.client.read.shortcircuit is set to true. If the string “_PORT” is present in this path, it will be replaced by the TCP port of the DataNode. Be careful about permissions for the directory that hosts the shared domain socket; dfsclient will complain if open to other users than the HBase user.
Default none
hbase.dfs.client.read.shortcircuit.buffer.size
If the DFSClient configuration dfs.client.read.shortcircuit.buffer.size is unset, we will use what is configured here as the short circuit read default direct byte buffer size. DFSClient native default is 1MB; HBase keeps its HDFS files open so number of file blocks * 1MB soon starts to add up and threaten OOME because of a shortage of direct memory. So, we set it down from the default. Make it > the default hbase block size set in the HColumnDescriptor which is usually 64k.
Default 131072
hbase.regionserver.checksum.verify
If set to true (the default), HBase verifies the checksums for hfile blocks. HBase writes checksums inline with the data when it writes out hfiles. HDFS (as of this writing) writes checksums to a separate file than the data file necessitating extra seeks. Setting this flag saves some on i/o. Checksum verification by HDFS will be internally disabled on hfile streams when this flag is set. If the hbase-checksum verification fails, we will switch back to using HDFS checksums (so do not disable HDFS checksums! And besides this feature applies to hfiles only, not to WALs). If this parameter is set to false, then hbase will not verify any checksums, instead it will depend on checksum verification being done in the HDFS client.
Default true
hbase.hstore.bytes.per.checksum
Number of bytes in a newly created checksum chunk for HBase-level checksums in hfile blocks.
Default 16384
hbase.hstore.checksum.algorithm
Name of an algorithm that is used to compute checksums. Possible values are NULL, CRC32, CRC32C.
Default CRC32C
hbase.client.scanner.max.result.size
Maximum number of bytes returned when calling a scanner’s next method. Note that when a single row is larger than this limit the row is still returned completely. The default value is 2MB, which is good for 1ge networks. With faster and/or high latency networks this value should be increased.
Default 2097152
hbase.server.scanner.max.result.size
Maximum number of bytes returned when calling a scanner’s next method. Note that when a single row is larger than this limit the row is still returned completely. The default value is 100MB. This is a safety setting to protect the server from OOM situations.
Default 104857600
hbase.status.published
This setting activates the publication by the master of the status of the region server. When a region server dies and its recovery starts, the master will push this information to the client application, to let them cut the connection immediately instead of waiting for a timeout.
Default false
hbase.status.publisher.class
Implementation of the status publication with a multicast message.
Default org.apache.hadoop.hbase.master.ClusterStatusPublisher$MulticastPublisher
hbase.status.listener.class
Implementation of the status listener with a multicast message.
Default org.apache.hadoop.hbase.client.ClusterStatusListener$MulticastListener
hbase.status.multicast.address.ip
Multicast address to use for the status publication by multicast.
Default 226.1.1.3
hbase.status.multicast.address.port
Multicast port to use for the status publication by multicast.
Default 16100
hbase.dynamic.jars.dir
The directory from which the custom filter JARs can be loaded dynamically by the region server without the need to restart. However, an already loaded filter/co-processor class would not be un-loaded. See HBASE-1936 for more details. Does not apply to coprocessors.
Default ${hbase.rootdir}/lib
hbase.security.authentication
Controls whether or not secure authentication is enabled for HBase. Possible values are ‘simple’ (no authentication), and ‘kerberos’.
Default simple
hbase.rest.filter.classes
Servlet filters for REST service.
Default org.apache.hadoop.hbase.rest.filter.GzipFilter
hbase.master.loadbalancer.class
Class used to execute the regions balancing when the period occurs. See the class comment for more on how it works http://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.html It replaces the DefaultLoadBalancer as the default (since renamed as the SimpleLoadBalancer).
Default org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer
hbase.master.loadbalance.bytable
Factor Table name when the balancer runs. Default: false.
Default false
hbase.master.normalizer.class
Class used to execute the region normalization when the period occurs. See the class comment for more on how it works http://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/master/normalizer/SimpleRegionNormalizer.html
Default org.apache.hadoop.hbase.master.normalizer.SimpleRegionNormalizer
hbase.rest.csrf.enabled
Set to true to enable protection against cross-site request forgery (CSRF)
Default false
hbase.rest-csrf.browser-useragents-regex
A comma-separated list of regular expressions used to match against an HTTP request’s User-Agent header when protection against cross-site request forgery (CSRF) is enabled for REST server by setting hbase.rest.csrf.enabled to true. If the incoming User-Agent matches any of these regular expressions, then the request is considered to be sent by a browser, and therefore CSRF prevention is enforced. If the request’s User-Agent does not match any of these regular expressions, then the request is considered to be sent by something other than a browser, such as scripted automation. In this case, CSRF is not a potential attack vector, so the prevention is not enforced. This helps achieve backwards-compatibility with existing automation that has not been updated to send the CSRF prevention header.
Default Mozilla.,Opera.
hbase.security.exec.permission.checks
If this setting is enabled and ACL based access control is active (the AccessController coprocessor is installed either as a system coprocessor or on a table as a table coprocessor) then you must grant all relevant users EXEC privilege if they require the ability to execute coprocessor endpoint calls. EXEC privilege, like any other permission, can be granted globally to a user, or to a user on a per table or per namespace basis. For more information on coprocessor endpoints, see the coprocessor section of the HBase online manual. For more information on granting or revoking permissions using the AccessController, see the security section of the HBase online manual.
Default false
hbase.procedure.regionserver.classes
A comma-separated list of org.apache.hadoop.hbase.procedure.RegionServerProcedureManager procedure managers that are loaded by default on the active HRegionServer process. The lifecycle methods (init/start/stop) will be called by the active HRegionServer process to perform the specific globally barriered procedure. After implementing your own RegionServerProcedureManager, just put it in HBase’s classpath and add the fully qualified class name here.
Default none
hbase.procedure.master.classes
A comma-separated list of org.apache.hadoop.hbase.procedure.MasterProcedureManager procedure managers that are loaded by default on the active HMaster process. A procedure is identified by its signature and users can use the signature and an instant name to trigger an execution of a globally barriered procedure. After implementing your own MasterProcedureManager, just put it in HBase’s classpath and add the fully qualified class name here.
Default none
hbase.coordinated.state.manager.class
Fully qualified name of class implementing coordinated state manager.
Default org.apache.hadoop.hbase.coordination.ZkCoordinatedStateManager
hbase.regionserver.storefile.refresh.period
The period (in milliseconds) for refreshing the store files for the secondary regions. 0 means this feature is disabled. Secondary regions sees new files (from flushes and compactions) from primary once the secondary region refreshes the list of files in the region (there is no notification mechanism). But too frequent refreshes might cause extra Namenode pressure. If the files cannot be refreshed for longer than HFile TTL (hbase.master.hfilecleaner.ttl) the requests are rejected. Configuring HFile TTL to a larger value is also recommended with this setting.
Default 0
hbase.region.replica.replication.enabled
Whether asynchronous WAL replication to the secondary region replicas is enabled or not. If this is enabled, a replication peer named “region_replica_replication” will be created which will tail the logs and replicate the mutations to region replicas for tables that have region replication > 1. If this is enabled once, disabling this replication also requires disabling the replication peer using shell or Admin java class. Replication to secondary region replicas works over standard inter-cluster replication.
Default false
hbase.http.filter.initializers
A comma separated list of class names. Each class in the list must extend org.apache.hadoop.hbase.http.FilterInitializer. The corresponding Filter will be initialized. Then, the Filter will be applied to all user facing jsp and servlet web pages. The ordering of the list defines the ordering of the filters. The default StaticUserWebFilter add a user principal as defined by the hbase.http.staticuser.user property.
Default org.apache.hadoop.hbase.http.lib.StaticUserWebFilter
hbase.security.visibility.mutations.checkauths
This property if enabled, will check whether the labels in the visibility expression are associated with the user issuing the mutation
Default false
hbase.http.max.threads
The maximum number of threads that the HTTP Server will create in its ThreadPool.
Default 16
hbase.replication.rpc.codec
The codec that is to be used when replication is enabled so that the tags are also replicated. This is used along with HFileV3 which supports tags in them. If tags are not used or if the hfile version used is HFileV2 then KeyValueCodec can be used as the replication codec. Note that using KeyValueCodecWithTags for replication when there are no tags causes no harm.
Default org.apache.hadoop.hbase.codec.KeyValueCodecWithTags
hbase.replication.source.maxthreads
The maximum number of threads any replication source will use for shipping edits to the sinks in parallel. This also limits the number of chunks each replication batch is broken into. Larger values can improve the replication throughput between the master and slave clusters. The default of 10 will rarely need to be changed.
Default 10
hbase.http.staticuser.user
The user name to filter as, on static web filters while rendering content. An example use is the HDFS web UI (user to be used for browsing files).
Default dr.stack
hbase.regionserver.handler.abort.on.error.percent
The percent of region server RPC threads failed to abort RS. -1 Disable aborting; 0 Abort if even a single handler has died; 0.x Abort only when this percent of handlers have died; 1 Abort only all of the handers have died.
Default 0.5
hbase.mob.file.cache.size
Number of opened file handlers to cache. A larger value will benefit reads by providing more file handlers per mob file cache and would reduce frequent file opening and closing. However, if this is set too high, this could lead to a “too many opened file handlers” The default value is 1000.
Default 1000
hbase.mob.cache.evict.period
The amount of time in seconds before the mob cache evicts cached mob files. The default value is 3600 seconds.
Default 3600
hbase.mob.cache.evict.remain.ratio
The ratio (between 0.0 and 1.0) of files that remains cached after an eviction is triggered when the number of cached mob files exceeds the hbase.mob.file.cache.size. The default value is 0.5f.
Default 0.5f
hbase.master.mob.ttl.cleaner.period
The period that ExpiredMobFileCleanerChore runs. The unit is second. The default value is one day. The MOB file name uses only the date part of the file creation time in it. We use this time for deciding TTL expiry of the files. So the removal of TTL expired files might be delayed. The max delay might be 24 hrs.
Default 86400
hbase.mob.compaction.mergeable.threshold
If the size of a mob file is less than this value, it’s regarded as a small file and needs to be merged in mob compaction. The default value is 1280MB.
Default 1342177280
hbase.mob.delfile.max.count
The max number of del files that is allowed in the mob compaction. In the mob compaction, when the number of existing del files is larger than this value, they are merged until number of del files is not larger this value. The default value is 3.
Default 3
hbase.mob.compaction.batch.size
The max number of the mob files that is allowed in a batch of the mob compaction. The mob compaction merges the small mob files to bigger ones. If the number of the small files is very large, it could lead to a “too many opened file handlers” in the merge. And the merge has to be split into batches. This value limits the number of mob files that are selected in a batch of the mob compaction. The default value is 100.
Default 100
hbase.mob.compaction.chore.period
The period that MobCompactionChore runs. The unit is second. The default value is one week.
Default 604800
hbase.mob.compactor.class
Implementation of mob compactor, the default one is PartitionedMobCompactor.
Default org.apache.hadoop.hbase.mob.compactions.PartitionedMobCompactor
hbase.mob.compaction.threads.max
The max number of threads used in MobCompactor.
Default 1
hbase.snapshot.master.timeout.millis
Timeout for master for the snapshot procedure execution.
Default 300000
hbase.snapshot.region.timeout
Timeout for regionservers to keep threads in snapshot request pool waiting.
Default 300000
hbase.rpc.rows.warning.threshold
Number of rows in a batch operation above which a warning will be logged.
Default 5000
hbase.master.wait.on.service.seconds
Default is 5 minutes. Make it 30 seconds for tests. See HBASE-19794 for some context.
Default 30
hbase-env.sh
Set HBase environment variables in this file. Examples include options to pass the JVM on start of an HBase daemon such as heap size and garbage collector configs. You can also set configurations for HBase configuration, log directories, niceness, ssh options, where to locate process pid files, etc. Open the file at conf/hbase-env.sh and peruse its content. Each option is fairly well documented. Add your own environment variables here if you want them read by HBase daemons on startup.
Changes here will require a cluster restart for HBase to notice the change.
log4j.properties
Edit this file to change rate at which HBase files are rolled and to change the level at which HBase logs messages.
Changes here will require a cluster restart for HBase to notice the change though log levels can be changed for particular daemons via the HBase UI.
Deploying HBase
This section provides information to help you plan the capacity of an HBase cluster and the size of its RegionServers.
Node Count and JVM Configuration – The number of nodes in an HBase cluster is typically driven by physical size of the data set and read/write throughput.
Physical Size of the Data – The physical size of data on disk is affected by the following factors:
| Factor Affecting Size of Physical Data | Description |
| HBase Overhead | The default amount of disk space required for a single HBase table cell. Smaller table cells require less overhead. The minimum cell size is 24 bytes and the default maximum is 10485760 bytes.
You can customize the maximum cell size by using the hbase.client.keyvalue.maxsize property in the hbase-site.xml configuration file. HBase table cells are aggregated into blocks; you can configure the block size for each column family by using the hbase.mapreduce.hfileoutputformat.blocksize property. The default value is 65536 bytes. You can reduce this value for tables with highly random data access patterns if you want to improve query latency. |
| Compression | You should choose the data compression tool that is most appropriate to reducing the physical size of your data on disk. Although HBase is not shipped with LZO due to licensing issues, you can install LZO after installing HBase. GZIP provides better compression than LZO but is slower. HBase also supports Snappy. |
| HDFS Replication | HBase uses HDFS for storage, so replicating HBase data stored in HDFS affects the total physical size of data. A typical replication factor of 3 for all HBase tables in a cluster triples the physical size of the stored data. |
| HDFS Replication | HBase uses HDFS for storage, so replicating HBase data stored in HDFS affects the total physical size of data. A typical replication factor of 3 for all HBase tables |
| RegionServer Write Ahead Log (WAL) | The size of the Write Ahead Log, or WAL, for each RegionServer has minimal impact on the physical size of data: typically fixed at less than half of the memory for the RegionServer. The data size of WAL is usually not configured. |
Read/Write Throughput – The number of nodes in an HBase cluster might also be driven by required throughput for disk reads and writes. The throughput per node greatly depends on table cell size and data request patterns, as well as node and cluster configuration. You can use YCSB tools to test the throughput of a single node or a cluster to determine if read/write throughput should drive the number of nodes in your HBase cluster. A typical throughput for write operations for one RegionServer is 5 through 15 MB/s. Unfortunately, there is no good estimate for read throughput, which varies greatly depending on physical data size, request patterns, and hit rate for the block cache.
Region Count and Size – In general, an HBase cluster runs more smoothly with fewer regions. Although administrators cannot directly configure the number of regions for a RegionServer, they can indirectly increase the number of regions in the following ways:
- Increase the size of the MemStore for a RegionServer
- Increase the size of a region
Increase MemStore size for RegionServer – If you are an administrator, you can adjust the size of the MemStore in hbase-site.xml configuration file depending on your need. Use of the RegionServer MemStore largely determines the maximum number of regions for the RegionServer. Each region has one MemStore for each column family, which grows to a configurable size, usually between 128 and 256 MB. Administrators specify this size by using the hbase.hregion.memstore.flush.size property in the hbase-site.xml configuration file. The RegionServer dedicates some fraction of total memory to region MemStores based on the value of the hbase.regionserver.global.memstore.size configuration property. If usage exceeds this configurable size, HBase might become unresponsive or compaction storms might occur.
You can use the following formula to estimate the number of regions for a RegionServer:
(regionserver_memory_size) * (memstore_fraction) / ((memstore_size) * (num_column_families))
For example, assume that your environment uses the following configuration:
- RegionServer with 16 GB RAM (or 16384 MB)
- MemStore fraction of .4
- MemStore with 128 MB RAM
- One column family in table
The formula for this configuration is as follows:
(16384 MB * .4) / ((128 MB * 1) = approximately 51 regions
You can adjust the memory consumption of the regions for this example RegionServer by increasing the RAM size of the memstore to 256 MB. The reconfigured RegionServer then has MemStore space for approximately 25 regions, and the HBase cluster should run more smoothly given a uniform distribution of load. The formula can be used for multiple tables with the same configuration by using the total number of column families in all the tables.
If the data request pattern is dominated by write operations rather than read operations, you should increase the MemStore fraction. However, this increase negatively impacts the block cache.
Increase Size of Region – The other way to indirectly increase the number of regions for a RegionServer is to increase the size of the region by using the hbase.hregion.max.filesize property in the hbase-site.xml configuration file. Administrators increase the number of regions for a RegionServer by increasing the specified size at which new regions are dynamically allocated.
Maximum region size is primarily limited by compactions. Very large compactions can degrade cluster performance. The recommended maximum region size is 10 through 20 GB. For HBase clusters running version 0.90.x, the maximum recommended region size is 4 GB and the default is 256 MB. If you are unable to estimate the size of your tables, you should retain the default value. You should increase the region size only if your table cells tend to be 100 KB or larger.
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