一、前言
主要針對HBase的1.2.3版本參照官網，對其常用配置參數進行翻譯說明，供查閱。
二、配置參數說明
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<!-- hbase的本地臨時目錄,每次機器重啓數據會丟失，建議放到某個持久化文件目錄下 -->
<property>
<name>hbase.tmp.dir</name>
<value>${java.io.tmpdir}/hbase-${user.name}</value>
<description>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.
</description>
</property>
<!-- 每個regionServer的共享目錄,用來持久化Hbase,默認情況下在/tmp/hbase下面 -->
<property>
<name>hbase.rootdir</name>
<value>${hbase.tmp.dir}/hbase</value>
<description>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 ${hbase.tmp.dir} is set too -- usually /tmp --
so change this configuration or else all data will be lost on
machine restart.
</description>
</property>
<!-- hbase底層如果使用hdfs作爲文件系統，這裏是指默認在文件系統的臨時存儲目錄用來存儲臨時數據 -->
<property>
<name>hbase.fs.tmp.dir</name>
<value>/user/${user.name}/hbase-staging</value>
<description>A staging directory in default file system (HDFS)
for keeping temporary data.
</description>
</property>
<!-- hdfs裏面批量裝載的目錄 -->
<property>
<name>hbase.bulkload.staging.dir</name>
<value>${hbase.fs.tmp.dir}</value>
<description>A staging directory in default file system (HDFS)
for bulk loading.
</description>
</property>
<!-- hbase集羣模式,false表示hbase的單機，true表示是分佈式模式 -->
<property>
<name>hbase.cluster.distributed</name>
<value>false</value>
<description>The mode the cluster will be in. Possible values are
false for standalone mode and true for distributed mode. If
false, startup will run all HBase and ZooKeeper daemons together
in the one JVM.
</description>
</property>
<!-- hbase依賴的zk地址 -->
<property>
<name>hbase.zookeeper.quorum</name>
<value>localhost</value>
<description>Comma separated list of servers in the ZooKeeper ensemble
(This config. should have been named hbase.zookeeper.ensemble).
For example, "host1.mydomain.com,host2.mydomain.com,host3.mydomain.com".
By default this is set to localhost for local and pseudo-distributed
modes
of operation. For a fully-distributed setup, this should be set to a
full
list of ZooKeeper ensemble servers. If HBASE_MANAGES_ZK is set in
hbase-env.sh
this is the list of servers which hbase will start/stop ZooKeeper on as
part of cluster start/stop. Client-side, we will take this list of
ensemble members and put it together with the
hbase.zookeeper.clientPort
config. and pass it into zookeeper constructor as the connectString
parameter.
</description>
</property>
<!-- 如果是本地存儲，位於本地文件系統的路徑 -->
<property>
<name>hbase.local.dir</name>
<value>${hbase.tmp.dir}/local/</value>
<description>Directory on the local filesystem to be used
as a local storage.
</description>
</property>
<!-- hbase master節點的端口 -->
<property>
<name>hbase.master.port</name>
<value>16000</value>
<description>The port the HBase Master should bind to.</description>
</property>
<!-- hbase master的web ui頁面的端口 -->
<property>
<name>hbase.master.info.port</name>
<value>16010</value>
<description>The port for the HBase Master web UI.
Set to -1 if you do not want a UI instance run.
</description>
</property>
<!-- hbase master的web ui頁面綁定的地址 -->
<property>
<name>hbase.master.info.bindAddress</name>
<value>0.0.0.0</value>
<description>The bind address for the HBase Master web UI
</description>
</property>
<!-- 不知道幹什麼用 -->
<property>
<name>hbase.master.logcleaner.plugins</name>
<value>org.apache.hadoop.hbase.master.cleaner.TimeToLiveLogCleaner
</value>
<description>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.
</description>
</property>
<!-- hbase清理oldlogdir目錄下的hlog文件的最長時間 ，單位毫秒 -->
<property>
<name>hbase.master.logcleaner.ttl</name>
<value>600000</value>
<description>Maximum time a WAL can stay in the .oldlogdir directory,
after which it will be cleaned by a Master thread.
</description>
</property>
<property>
<name>hbase.master.hfilecleaner.plugins</name>
<value>org.apache.hadoop.hbase.master.cleaner.TimeToLiveHFileCleaner
</value>
<description>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.
</description>
</property>
<!-- 不知道幹嘛的 -->
<property>
<name>hbase.master.catalog.timeout</name>
<value>600000</value>
<description>Timeout value for the Catalog Janitor from the master to
META.
</description>
</property>
<!-- master是否監聽master web ui端口並重定向請求給web ui服務器，該配置是master和RegionServer共享 -->
<property>
<name>hbase.master.infoserver.redirect</name>
<value>true</value>
<description>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.
</description>
</property>
<!-- hbase regionServer的默認端口 -->
<property>
<name>hbase.regionserver.port</name>
<value>16020</value>
<description>The port the HBase RegionServer binds to.</description>
</property>
<!-- hbase regionServer的web ui的默認端口 -->
<property>
<name>hbase.regionserver.info.port</name>
<value>16030</value>
<description>The port for the HBase RegionServer web UI
Set to -1 if you do not want the RegionServer UI to run.
</description>
</property>
<!-- hbase regionServer的web ui綁定地址 -->
<property>
<name>hbase.regionserver.info.bindAddress</name>
<value>0.0.0.0</value>
<description>The address for the HBase RegionServer web UI
</description>
</property>
<!-- 如果regionServer默認的端口被暫用了，是否允許hbase搜索一個可用的端口來綁定 -->
<property>
<name>hbase.regionserver.info.port.auto</name>
<value>false</value>
<description>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.
</description>
</property>
<!-- regionServer端默認開啓的RPC監控實例數，也即RegionServer能夠處理的IO請求線程數 -->
<property>
<name>hbase.regionserver.handler.count</name>
<value>30</value>
<description>Count of RPC Listener instances spun up on RegionServers.
Same property is used by the Master for count of master handlers.
</description>
</property>
<!-- hbase提供的可以用來處理請求的隊列數 0.1 * 總數，如果爲0則表示所有請求公用一個隊列， 如果爲1則表示每個請求自己有一個獨立的隊列 -->
<property>
<name>hbase.ipc.server.callqueue.handler.factor</name>
<value>0.1</value>
<description>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.
</description>
</property>
<!-- hbase提供的讀寫隊列數比例,參數值爲0-1之間，如果爲0則所有隊列同時處理讀寫請求 -->
<!-- 現在假設我們有10個隊列 1、該值設置爲0，則這10個隊列同時處理讀寫請求 2、該值設置爲1，則1個隊列處理寫情況，9個隊列處理讀請求
3、該值設置爲0.x,則x個隊列處理處理讀請求，10-x個隊列處理寫請求 4、根據實際情況，讀多寫少還是寫少讀多，可按需配置 -->
<property>
<name>hbase.ipc.server.callqueue.read.ratio</name>
<value>0</value>
<description>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.
</description>
</property>
<!-- hbase提供的用於支持get/scan請求的隊列比例 -->
<property>
<name>hbase.ipc.server.callqueue.scan.ratio</name>
<value>0</value>
<description>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.
</description>
</property>
<!-- regionServer發送消息給Master的時間間隔,單位是毫秒 -->
<property>
<name>hbase.regionserver.msginterval</name>
<value>3000</value>
<description>Interval between messages from the RegionServer to Master
in milliseconds.
</description>
</property>
<!-- regionServer日誌滾動提交的週期,不管這個日誌有沒有寫滿 -->
<property>
<name>hbase.regionserver.logroll.period</name>
<value>3600000</value>
<description>Period at which we will roll the commit log regardless
of how many edits it has.
</description>
</property>
<!-- 在regionServer上的WAL日誌，在停止服務前允許的關閉 WAL 的連續錯誤數量 比如如果我們日誌在滾動提交的是，此時wal寫入錯誤，那麼就會立即停止regionServer的服務
默認值2表示運行有2個錯誤發生 -->
<property>
<name>hbase.regionserver.logroll.errors.tolerated</name>
<value>2</value>
<description>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.
</description>
</property>
<!-- regionServer的WAL文件讀取的實現類 -->
<property>
<name>hbase.regionserver.hlog.reader.impl</name>
<value>org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader
</value>
<description>The WAL file reader implementation.</description>
</property>
<!-- regionServer的WAL文件寫的實現類 -->
<property>
<name>hbase.regionserver.hlog.writer.impl</name>
<value>org.apache.hadoop.hbase.regionserver.wal.ProtobufLogWriter
</value>
<description>The WAL file writer implementation.</description>
</property>
<!-- regionServer的全局memstore的大小，超過該大小會觸發flush到磁盤的操作,默認是堆大小的40%,而且regionserver級別的
flush會阻塞客戶端讀寫 -->
<property>
<name>hbase.regionserver.global.memstore.size</name>
<value></value>
<description>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
emtpy in order to
honor the old hbase.regionserver.global.memstore.upperLimit property if
present.
</description>
</property>
<!--可以理解爲一個安全的設置，有時候集羣的“寫負載”非常高，寫入量一直超過flush的量，這時，我們就希望memstore不要超過一定的安全設置。
在這種情況下，寫操作就要被阻塞一直到memstore恢復到一個“可管理”的大小, 這個大小就是默認值是堆大小 * 0.4 * 0.95，也就是當regionserver級別
的flush操作發送後,會阻塞客戶端寫,一直阻塞到整個regionserver級別的memstore的大小爲 堆大小 * 0.4 *0.95爲止 -->
<property>
<name>hbase.regionserver.global.memstore.size.lower.limit</name>
<value></value>
<description>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
emtpy in order to
honor the old hbase.regionserver.global.memstore.lowerLimit property if
present.
</description>
</property>
<!-- 內存中的文件在自動刷新之前能夠存活的最長時間，默認是1h -->
<property>
<name>hbase.regionserver.optionalcacheflushinterval</name>
<value>3600000</value>
<description>
Maximum amount of time an edit lives in memory before being automatically
flushed.
Default 1 hour. Set it to 0 to disable automatic flushing.
</description>
</property>
<property>
<name>hbase.regionserver.catalog.timeout</name>
<value>600000</value>
<description>Timeout value for the Catalog Janitor from the
regionserver to META.</description>
</property>
<!-- 當使用dns的時候，regionServer用來上報IP地址的網絡接口名字 -->
<property>
<name>hbase.regionserver.dns.interface</name>
<value>default</value>
<description>The name of the Network Interface from which a region
server
should report its IP address.
</description>
</property>
<!-- 當使用DNS的時候，RegionServer使用的DNS的域名或者IP 地址，RegionServer用它來確定和master用來進行通訊的域名 -->
<property>
<name>hbase.regionserver.dns.nameserver</name>
<value>default</value>
<description>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.
</description>
</property>
<!-- region在切分的時候的默認切分策略 -->
<property>
<name>hbase.regionserver.region.split.policy</name>
<value>org.apache.hadoop.hbase.regionserver.IncreasingToUpperBoundRegionSplitPolicy
</value>
<description>
A split policy determines when a region should be split. The various
other split policies that
are available currently are ConstantSizeRegionSplitPolicy,
DisabledRegionSplitPolicy,
DelimitedKeyPrefixRegionSplitPolicy, KeyPrefixRegionSplitPolicy etc.
</description>
</property>
<!-- 當某個HRegionServer上的region到達這個限制時，不會在進行region切分，也就是一個HRegionServer默認最大允許有1000個region -->
<property>
<name>hbase.regionserver.regionSplitLimit</name>
<value>1000</value>
<description>
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.
</description>
</property>
<!-- zk sesscion超時時間 -->
<property>
<name>zookeeper.session.timeout</name>
<value>90000</value>
<description>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 a 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.
</description>
</property>
<!-- hbase在zk上默認的根目錄 -->
<property>
<name>zookeeper.znode.parent</name>
<value>/hbase</value>
<description>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 path are configured with a
relative path, so they will all go under this directory unless
changed.
</description>
</property>
<!-- hbase在zk上的節點路徑 -->
<property>
<name>zookeeper.znode.rootserver</name>
<value>root-region-server</value>
<description>Path to ZNode holding root region location. This is
written by
the master and read by clients and region servers. If a relative path is
given, the parent folder will be ${zookeeper.znode.parent}. By
default,
this means the root location is stored at /hbase/root-region-server.
</description>
</property>
<!-- hbase在zk上節點使用的權限 -->
<property>
<name>zookeeper.znode.acl.parent</name>
<value>acl</value>
<description>Root ZNode for access control lists.</description>
</property>
<property>
<name>hbase.zookeeper.dns.interface</name>
<value>default</value>
<description>The name of the Network Interface from which a ZooKeeper
server
should report its IP address.
</description>
</property>
<property>
<name>hbase.zookeeper.dns.nameserver</name>
<value>default</value>
<description>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.
</description>
</property>
<!-- zk的使用端口 -->
<property>
<name>hbase.zookeeper.peerport</name>
<value>2888</value>
<description>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.
</description>
</property>
<!-- zk直接執行leader選舉時通訊的端口 -->
<property>
<name>hbase.zookeeper.leaderport</name>
<value>3888</value>
<description>Port used by ZooKeeper for leader election.
See
http://hadoop.apache.org/zookeeper/docs/r3.1.1/zookeeperStarted.html#sc_RunningReplicatedZooKeeper
for more information.
</description>
</property>
<!-- zk是否支持多重更新 -->
<property>
<name>hbase.zookeeper.useMulti</name>
<value>true</value>
<description>Instructs HBase to make use of ZooKeeper's multi-update
functionality.
This allows certain ZooKeeper operations to complete more quickly and
prevents some issues
with rare Replication failure scenarios (see the release note of
HBASE-2611 for an example).
IMPORTANT: only set this to true if all ZooKeeper servers in the cluster are on
version 3.4+
and will not be downgraded. ZooKeeper versions before 3.4 do not support
multi-update and
will not fail gracefully if multi-update is invoked (see ZOOKEEPER-1495).
</description>
</property>
<!-- 是否允許HBaseConfiguration去讀取zk的配置文件，不清楚意義是什麼? -->
<property>
<name>hbase.config.read.zookeeper.config</name>
<value>false</value>
<description>
Set to true to allow HBaseConfiguration to read the
zoo.cfg file for ZooKeeper properties. Switching this to true
is not recommended, since the functionality of reading ZK
properties from a zoo.cfg file has been deprecated.
</description>
</property>
<property>
<name>hbase.zookeeper.property.initLimit</name>
<value>10</value>
<description>Property from ZooKeeper's config zoo.cfg.
The number of ticks that the initial synchronization phase can take.
</description>
</property>
<property>
<name>hbase.zookeeper.property.syncLimit</name>
<value>5</value>
<description>Property from ZooKeeper's config zoo.cfg.
The number of ticks that can pass between sending a request and getting
an
acknowledgment.
</description>
</property>
<property>
<name>hbase.zookeeper.property.dataDir</name>
<value>${hbase.tmp.dir}/zookeeper</value>
<description>Property from ZooKeeper's config zoo.cfg.
The directory where the snapshot is stored.
</description>
</property>
<property>
<name>hbase.zookeeper.property.clientPort</name>
<value>2181</value>
<description>Property from ZooKeeper's config zoo.cfg.
The port at which the clients will connect.
</description>
</property>
<property>
<name>hbase.zookeeper.property.maxClientCnxns</name>
<value>300</value>
<description>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.
</description>
</property>
<!--Client configurations -->
<!-- hbase客戶端每次 寫緩衝的大小(也就是客戶端批量提交到server端)，這塊大小會同時佔用客戶端和服務端，緩衝區更大可以減少RPC次數，但是更大意味着內存佔用更多 -->
<property>
<name>hbase.client.write.buffer</name>
<value>2097152</value>
<description>Default size of the HTable client 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
</description>
</property>
<!-- 在hbase發生請求失敗的情況下,每次重試的等待時間 ,如果某段時間網絡持續不好,重試會一直髮生,如果還是連不上,就會放棄連接,在重試的過程中,會阻塞其它線程來搶鎖,如果長時間的超時會導致業務處理的阻塞 -->
<property>
<name>hbase.client.pause</name>
<value>100</value>
<description>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.
</description>
</property>
<!--重試次數，如果連不上或者fail，會重試 -->
<property>
<name>hbase.client.retries.number</name>
<value>35</value>
<description>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.
</description>
</property>
<!-- 單個Htable實例發送給集羣的最大任務數,也就是同一個實例最大的併發數 -->
<property>
<name>hbase.client.max.total.tasks</name>
<value>100</value>
<description>The maximum number of concurrent tasks a single HTable
instance will
send to the cluster.
</description>
</property>
<!-- 單個Htable實例發給regionServer的最大的任務併發數 -->
<property>
<name>hbase.client.max.perserver.tasks</name>
<value>5</value>
<description>The maximum number of concurrent tasks a single HTable
instance will
send to a single region server.
</description>
</property>
<!-- 客戶端到一個region的最大連接數，也就是說如果一個客戶端有超過配置項值到某個region的連接，後面的請求會被阻塞 -->
<property>
<name>hbase.client.max.perregion.tasks</name>
<value>1</value>
<description>The maximum number of concurrent connections 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.
</description>
</property>
<!-- 在執行hbase scan操作的時候，客戶端緩存的行數，設置小意味着更多的rpc次數，設置大比較吃內存 -->
<property>
<name>hbase.client.scanner.caching</name>
<value>2147483647</value>
<description>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
</description>
</property>
<!--一個KeyValue實例的最大大小，這是存儲文件中一個entry的容量上限,因爲一個KeyValue是不能分割的， 所有可以避免因爲數據過大導致region不可分割 -->
<property>
<name>hbase.client.keyvalue.maxsize</name>
<value>10485760</value>
<description>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.
</description>
</property>
<!-- scan操作中單次rpc的超時時間(比較重要的參數) -->
<property>
<name>hbase.client.scanner.timeout.period</name>
<value>60000</value>
<description>Client scanner lease period in milliseconds.
</description>
</property>
<property>
<name>hbase.client.localityCheck.threadPoolSize</name>
<value>2</value>
</property>
<!--Miscellaneous configuration -->
<property>
<name>hbase.bulkload.retries.number</name>
<value>10</value>
<description>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.
</description>
</property>
<property>
<name>hbase.balancer.period</name>
<value>300000</value>
<description>Period at which the region balancer runs in the Master.
</description>
</property>
<property>
<name>hbase.normalizer.period</name>
<value>1800000</value>
<description>Period at which the region normalizer runs in the Master.
</description>
</property>
<!-- HRegion負載遷移的時候的一個配置參數,具體怎麼用可看HMaster裏面的負載遷移的源代碼 -->
<property>
<name>hbase.regions.slop</name>
<value>0.2</value>
<description>Rebalance if any regionserver has average + (average *
slop) regions.</description>
</property>
<!-- 每次線程喚醒的週期 -->
<property>
<name>hbase.server.thread.wakefrequency</name>
<value>10000</value>
<description>Time to sleep in between searches for work (in
milliseconds).
Used as sleep interval by service threads such as log roller.
</description>
</property>
<property>
<name>hbase.server.versionfile.writeattempts</name>
<value>3</value>
<description>
How many time to retry attempting to write a version file
before just aborting. Each attempt is seperated by the
hbase.server.thread.wakefrequency milliseconds.
</description>
</property>
<!-- 單個region裏memstore的緩存大小，超過那麼整個HRegion就會flush,默認128M -->
<property>
<name>hbase.hregion.memstore.flush.size</name>
<value>134217728</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.hregion.percolumnfamilyflush.size.lower.bound</name>
<value>16777216</value>
<description>
If FlushLargeStoresPolicy is used, then every time that we hit the
total memstore limit, we find out all the column families whose
memstores
exceed this value, and only flush them, while retaining the others whose
memstores are lower than this limit. If none of the families have
their
memstore size more than this, all the memstores will be flushed
(just as usual). This value should be less than half of the total memstore
threshold (hbase.hregion.memstore.flush.size).
</description>
</property>
<!--當一個 region 中的 memstore 的大小大於這個值的時候，我們又觸發 了 close.會先運行“pre-flush”操作，清理這個需要關閉的
memstore，然後 將這個 region 下線。當一個 region 下線了，我們無法再進行任何寫操作。 如果一個 memstore 很大的時候，flush
操作會消耗很多時間。"pre-flush" 操作意味着在 region 下線之前，會先把 memstore 清空。這樣在最終執行 close 操作的時候，flush
操作會很快。 -->
<property>
<name>hbase.hregion.preclose.flush.size</name>
<value>5242880</value>
<description>
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.
</description>
</property>
<!-- 當一個HRegion上的memstore的大小滿足hbase.hregion.memstore.block.multiplier *
hbase.hregion.memstore.flush.size, 這個HRegion會執行flush操作並阻塞對該HRegion的寫入 -->
<property>
<name>hbase.hregion.memstore.block.multiplier</name>
<value>4</value>
<description>
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.
</description>
</property>
<!-- 設置爲true,有效減少在高併發寫時候的內存碎片 -->
<property>
<name>hbase.hregion.memstore.mslab.enabled</name>
<value>true</value>
<description>
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.
</description>
</property>
<!--HStoreFile最大的大小，當某個region的某個列族超過這個大小會進行region拆分 -->
<property>
<name>hbase.hregion.max.filesize</name>
<value>10737418240</value>
<description>
Maximum HStoreFile size. If any one of a column families' HStoreFiles has
grown to exceed this value, the hosting HRegion is split in two.
</description>
</property>
<!-- 一個region進行 major compaction合併的週期,在這個點的時候， 這個region下的所有hfile會進行合併,默認是7天,major
compaction非常耗資源,建議生產關閉(設置爲0)，在應用空閒時間手動觸發 -->
<property>
<name>hbase.hregion.majorcompaction</name>
<value>604800000</value>
<description>The time (in miliseconds) between 'major' compactions of
all
HStoreFiles in a region. Default: Set to 7 days. Major compactions tend to
happen exactly when you need them least so enable them such that they
run at
off-peak for your deploy; or, since this setting is on a periodicity that is
unlikely to match your loading, run the compactions via an external
invocation out of a cron job or some such.
</description>
</property>
<!-- 一個抖動比例，意思是說上一個參數設置是7天進行一次合併，也可以有50%的抖動比例 -->
<property>
<name>hbase.hregion.majorcompaction.jitter</name>
<value>0.50</value>
<description>Jitter outer bound for major compactions.
On each regionserver, we multiply the hbase.region.majorcompaction
interval by some random fraction that is inside the bounds of this
maximum. We then add this + or - product to when the next
major compaction is to run. The idea is that major compaction
does happen on every regionserver at exactly the same time. The
smaller this number, the closer the compactions come together.
</description>
</property>
<!-- 一個store裏面允許存的hfile的個數，超過這個個數會被寫到新的一個hfile裏面 也即是每個region的每個列族對應的memstore在fulsh爲hfile的時候，默認情況下當有3個hfile的時候就會
對這些文件進行合併重寫爲一個新文件，設置個數越大可以減少觸發合併的時間，但是每次合併的時間就會越長 -->
<property>
<name>hbase.hstore.compactionThreshold</name>
<value>3</value>
<description>
If more than this number of HStoreFiles in any one HStore
(one HStoreFile is written per flush of memstore) then a compaction
is run to rewrite all HStoreFiles files as one. Larger numbers
put off compaction but when it runs, it takes longer to complete.
</description>
</property>
<!-- 執行flush操作的線程數,設置小了刷新操作會排隊，大了會增加底層hdfs的負載壓力 -->
<property>
<name>hbase.hstore.flusher.count</name>
<value>2</value>
<description>
The number of flush threads. With less threads, the memstore flushes
will be queued. With
more threads, the flush will be executed in parallel, increasing the hdfs
load. This can
lead as well to more compactions.
</description>
</property>
<!-- 每個store阻塞更新請求的閥值,表示如果當前hstore中文件數大於該值，系統將會強制執行compaction操作進行文件合併， 合併的過程會阻塞整個hstore的寫入,這樣有個好處是避免compaction操作趕不上Hfile文件的生成速率 -->
<property>
<name>hbase.hstore.blockingStoreFiles</name>
<value>10</value>
<description>
If more than this number of StoreFiles in any one Store
(one StoreFile is written per flush of MemStore) then updates are
blocked for this HRegion until a compaction is completed, or
until hbase.hstore.blockingWaitTime has been exceeded.
</description>
</property>
<!-- 每個store阻塞更新請求的超時時間，如果超過這個時間合併操作還未完成，阻塞也會取消 -->
<property>
<name>hbase.hstore.blockingWaitTime</name>
<value>90000</value>
<description>
The time an HRegion will block updates for after hitting the StoreFile
limit defined by hbase.hstore.blockingStoreFiles.
After this time has elapsed, the HRegion will stop blocking updates even
if a compaction has not been completed.
</description>
</property>
<!-- 每個minor compaction操作的 允許的最大hfile文件上限 -->
<property>
<name>hbase.hstore.compaction.max</name>
<value>10</value>
<description>Max number of HStoreFiles to compact per 'minor'
compaction.</description>
</property>
<!-- 在執行compaction操作的過程中，每次讀取hfile文件的keyValue個數 -->
<property>
<name>hbase.hstore.compaction.kv.max</name>
<value>10</value>
<description>How many KeyValues to read and then write in a batch when
flushing
or compacting. Do less if big KeyValues and problems with OOME.
Do more if wide, small rows.
</description>
</property>
<property>
<name>hbase.hstore.time.to.purge.deletes</name>
<value>0</value>
<description>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.
</description>
</property>
<property>
<name>hbase.storescanner.parallel.seek.enable</name>
<value>false</value>
<description>
Enables StoreFileScanner parallel-seeking in StoreScanner,
a feature which can reduce response latency under special conditions.
</description>
</property>
<property>
<name>hbase.storescanner.parallel.seek.threads</name>
<value>10</value>
<description>
The default thread pool size if parallel-seeking feature enabled.
</description>
</property>
<!--LRUBlockCache塊緩存的大小，默認爲堆大小的40% -->
<property>
<name>hfile.block.cache.size</name>
<value>0.4</value>
<description>Percentage of maximum heap (-Xmx setting) to allocate to
block cache
used by HFile/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.
</description>
</property>
<property>
<name>hfile.block.index.cacheonwrite</name>
<value>false</value>
<description>This allows to put non-root multi-level index blocks into
the block
cache at the time the index is being written.
</description>
</property>
<property>
<name>hfile.index.block.max.size</name>
<value>131072</value>
<description>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.
</description>
</property>
<!--bucketcache的工作模式,默認有3種可選擇，heap,offheap,file。其中heap由jvm分配內存存儲，offheap
由操作系統分配內存存儲 -->
<property>
<name>hbase.bucketcache.ioengine</name>
<value></value>
<description>Where to store the contents of the bucketcache. One of:
heap,
offheap, or file. If a file, set it to file:PATH_TO_FILE. See
http://hbase.apache.org/book.html#offheap.blockcache for more
information.
</description>
</property>
<!-- 默認爲true,意思是combinedcache裏面包括了LRU和bucketcache -->
<property>
<name>hbase.bucketcache.combinedcache.enabled</name>
<value>true</value>
<description>Whether or not the bucketcache is used in league with the
LRU
on-heap block cache. In this mode, indices and blooms are kept in the LRU
blockcache and the data blocks are kept in the bucketcache.
</description>
</property>
<!-- 就是bucketcache大小,如果配置的值在0-1直接,表示佔用堆內存的百分比,或者配置XXMB也可 -->
<property>
<name>hbase.bucketcache.size</name>
<value></value>
<description>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
</description>
</property>
<property>
<name>hbase.bucketcache.sizes</name>
<value></value>
<description>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 1024 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).
</description>
</property>
<property>
<name>hfile.format.version</name>
<value>3</value>
<description>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).
Distributed Log Replay requires that tags are enabled. Also see the
configuration
'hbase.replication.rpc.codec'.
</description>
</property>
<property>
<name>hfile.block.bloom.cacheonwrite</name>
<value>false</value>
<description>Enables cache-on-write for inline blocks of a compound
Bloom filter.</description>
</property>
<property>
<name>io.storefile.bloom.block.size</name>
<value>131072</value>
<description>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.
</description>
</property>
<property>
<name>hbase.rs.cacheblocksonwrite</name>
<value>false</value>
<description>Whether an HFile block should be added to the block cache
when the
block is finished.
</description>
</property>
<!-- 單次rpc請求的超時時間,如果某次RPC時間超過該值，客戶端就會主動關閉socket -->
<property>
<name>hbase.rpc.timeout</name>
<value>60000</value>
<description>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.
</description>
</property>
<!-- 該參數表示HBase客戶端發起一次數據操作(一次操作可能有多次rpc)直至得到響應之間總的超時時間 -->
<property>
<name>hbase.client.operation.timeout</name>
<value>1200000</value>
<description>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.
</description>
</property>
<property>
<name>hbase.cells.scanned.per.heartbeat.check</name>
<value>10000</value>
<description>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
</description>
</property>
<property>
<name>hbase.rpc.shortoperation.timeout</name>
<value>10000</value>
<description>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.
</description>
</property>
<property>
<name>hbase.ipc.client.tcpnodelay</name>
<value>true</value>
<description>Set no delay on rpc socket connections. See
http://docs.oracle.com/javase/1.5.0/docs/api/java/net/Socket.html#getTcpNoDelay()
</description>
</property>
<property>
<name>hbase.regionserver.hostname</name>
<value></value>
<description>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.
</description>
</property>
<!-- The following properties configure authentication information for HBase
processes when using Kerberos security. There are no default values, included
here for documentation purposes -->
<property>
<name>hbase.master.keytab.file</name>
<value></value>
<description>Full path to the kerberos keytab file to use for logging
in
the configured HMaster server principal.
</description>
</property>
<property>
<name>hbase.master.kerberos.principal</name>
<value></value>
<description>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.
</description>
</property>
<property>
<name>hbase.regionserver.keytab.file</name>
<value></value>
<description>Full path to the kerberos keytab file to use for logging
in
the configured HRegionServer server principal.
</description>
</property>
<property>
<name>hbase.regionserver.kerberos.principal</name>
<value></value>
<description>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
</description>
</property>
<!-- Additional configuration specific to HBase security -->
<property>
<name>hadoop.policy.file</name>
<value>hbase-policy.xml</value>
<description>The policy configuration file used by RPC servers to make
authorization decisions on client requests. Only used when HBase
security is enabled.
</description>
</property>
<property>
<name>hbase.superuser</name>
<value></value>
<description>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.
</description>
</property>
<property>
<name>hbase.auth.key.update.interval</name>
<value>86400000</value>
<description>The update interval for master key for authentication
tokens
in servers in milliseconds. Only used when HBase security is enabled.
</description>
</property>
<property>
<name>hbase.auth.token.max.lifetime</name>
<value>604800000</value>
<description>The maximum lifetime in milliseconds after which an
authentication token expires. Only used when HBase security is
enabled.
</description>
</property>
<property>
<name>hbase.ipc.client.fallback-to-simple-auth-allowed</name>
<value>false</value>
<description>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.
</description>
</property>
<property>
<name>hbase.ipc.server.fallback-to-simple-auth-allowed</name>
<value>false</value>
<description>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.
</description>
</property>
<property>
<name>hbase.coprocessor.enabled</name>
<value>true</value>
<description>Enables or disables coprocessor loading. If 'false'
(disabled), any other coprocessor related configuration will be
ignored.
</description>
</property>
<property>
<name>hbase.coprocessor.user.enabled</name>
<value>true</value>
<description>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.
</description>
</property>
<property>
<name>hbase.coprocessor.region.classes</name>
<value></value>
<description>A comma-separated list of 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, just
put
it in HBase's classpath and add the fully qualified class name here.
A coprocessor can also be loaded on demand by setting
HTableDescriptor.
</description>
</property>
<property>
<name>hbase.rest.port</name>
<value>8080</value>
<description>The port for the HBase REST server.</description>
</property>
<property>
<name>hbase.rest.readonly</name>
<value>false</value>
<description>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.
</description>
</property>
<property>
<name>hbase.rest.threads.max</name>
<value>100</value>
<description>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.
</description>
</property>
<property>
<name>hbase.rest.threads.min</name>
<value>2</value>
<description>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.
</description>
</property>
<property>
<name>hbase.rest.support.proxyuser</name>
<value>false</value>
<description>Enables running the REST server to support proxy-user
mode.</description>
</property>
<property skipInDoc="true">
<name>hbase.defaults.for.version</name>
<value>1.2.3</value>
<description>This defaults file was compiled for version
${project.version}. This variable is used
to make sure that a user doesn't have an old version of
hbase-default.xml on the
classpath.
</description>
</property>
<property>
<name>hbase.defaults.for.version.skip</name>
<value>false</value>
<description>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 RuntimException complaint: "hbase-default.xml file
seems to be for and old version of HBase (\${hbase.version}), this
version is X.X.X-SNAPSHOT"
</description>
</property>
<property>
<name>hbase.coprocessor.master.classes</name>
<value></value>
<description>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.
</description>
</property>
<property>
<name>hbase.coprocessor.abortonerror</name>
<value>true</value>
<description>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.
</description>
</property>
<property>
<name>hbase.online.schema.update.enable</name>
<value>true</value>
<description>Set true to enable online schema changes.</description>
</property>
<property>
<name>hbase.table.lock.enable</name>
<value>true</value>
<description>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.
</description>
</property>
<!-- hbase table單行row的最大大小 -->
<property>
<name>hbase.table.max.rowsize</name>
<value>1073741824</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.thrift.minWorkerThreads</name>
<value>16</value>
<description>The "core size" of the thread pool. New threads are
created on every
connection until this many threads are created.
</description>
</property>
<property>
<name>hbase.thrift.maxWorkerThreads</name>
<value>1000</value>
<description>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.
</description>
</property>
<property>
<name>hbase.thrift.maxQueuedRequests</name>
<value>1000</value>
<description>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.
</description>
</property>
<property>
<name>hbase.thrift.htablepool.size.max</name>
<value>1000</value>
<description>The upper bound for the table pool used in the Thrift
gateways server.
Since this is per table name, we assume a single table and so with 1000
default
worker threads max this is set to a matching number. For other workloads
this number
can be adjusted as needed.
</description>
</property>
<property>
<name>hbase.regionserver.thrift.framed</name>
<value>false</value>
<description>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.
</description>
</property>
<property>
<name>hbase.regionserver.thrift.framed.max_frame_size_in_mb</name>
<value>2</value>
<description>Default frame size when using framed transport
</description>
</property>
<property>
<name>hbase.regionserver.thrift.compact</name>
<value>false</value>
<description>Use Thrift TCompactProtocol binary serialization
protocol.</description>
</property>
<property>
<name>hbase.rootdir.perms</name>
<value>700</value>
<description>FS Permissions for the root directory in a
secure(kerberos) setup.
When master starts, it creates the rootdir with this permissions or sets
the permissions
if it does not match.
</description>
</property>
<property>
<name>hbase.data.umask.enable</name>
<value>false</value>
<description>Enable, if true, that file permissions should be assigned
to the files written by the regionserver
</description>
</property>
<property>
<name>hbase.data.umask</name>
<value>000</value>
<description>File permissions that should be used to write data
files when hbase.data.umask.enable is true
</description>
</property>
<property>
<name>hbase.metrics.showTableName</name>
<value>true</value>
<description>Whether to include the prefix "tbl.tablename" in
per-column family metrics.
If true, for each metric M, per-cf metrics will be reported for
tbl.T.cf.CF.M, if false,
per-cf metrics will be aggregated by column-family across tables, and
reported for cf.CF.M.
In both cases, the aggregated metric M across tables and cfs will be
reported.
</description>
</property>
<property>
<name>hbase.metrics.exposeOperationTimes</name>
<value>true</value>
<description>Whether to report metrics about time taken performing an
operation on the region server. Get, Put, Delete, Increment, and
Append can all
have their times exposed through Hadoop metrics per CF and per region.
</description>
</property>
<!-- 允許快照被使用 -->
-->
<property>
<name>hbase.snapshot.enabled</name>
<value>true</value>
<description>Set to true to allow snapshots to be taken / restored /
cloned.</description>
</property>
<!-- 在hbase重啓的時候，如果重啓失敗了，則使用快照代替，同時成功後刪除快照 -->
<property>
<name>hbase.snapshot.restore.take.failsafe.snapshot</name>
<value>true</value>
<description>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
</description>
</property>
<property>
<name>hbase.snapshot.restore.failsafe.name</name>
<value>hbase-failsafe-{snapshot.name}-{restore.timestamp}</value>
<description>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.
</description>
</property>
<!-- hbase.server.compactchecker.interval.multiplier * hbase.server.thread.wakefrequency
後臺線程每隔多久定期檢查是否需要執行compaction -->
<property>
<name>hbase.server.compactchecker.interval.multiplier</name>
<value>1000</value>
<description>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.
</description>
</property>
<property>
<name>hbase.lease.recovery.timeout</name>
<value>900000</value>
<description>How long we wait on dfs lease recovery in total before
giving up.</description>
</property>
<property>
<name>hbase.lease.recovery.dfs.timeout</name>
<value>64000</value>
<description>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.
</description>
</property>
<!-- hbase colume最大的版本數 -->
<property>
<name>hbase.column.max.version</name>
<value>1</value>
<description>New column family descriptors will use this value as the
default number of versions
to keep.
</description>
</property>
<property>
<name>hbase.dfs.client.read.shortcircuit.buffer.size</name>
<value>131072</value>
<description>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.
</description>
</property>
<property>
<name>hbase.regionserver.checksum.verify</name>
<value>true</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.hstore.bytes.per.checksum</name>
<value>16384</value>
<description>
Number of bytes in a newly created checksum chunk for HBase-level
checksums in hfile blocks.
</description>
</property>
<property>
<name>hbase.hstore.checksum.algorithm</name>
<value>CRC32C</value>
<description>
Name of an algorithm that is used to compute checksums. Possible values
are NULL, CRC32, CRC32C.
</description>
</property>
<!-- hbase客戶端scan操作的時候，每次遠程調用返回的最大字節數，默認是2M, 用來限制client從HRegionServer取到的bytes總數，bytes總數通過row的KeyValue計算得出 -->
<property>
<name>hbase.client.scanner.max.result.size</name>
<value>2097152</value>
<description>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.
</description>
</property>
<!-- hbase服務端對scan請求返回的結果大小做限制 -->
<property>
<name>hbase.server.scanner.max.result.size</name>
<value>104857600</value>
<description>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.
</description>
</property>
<property>
<name>hbase.status.published</name>
<value>false</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.status.publisher.class</name>
<value>org.apache.hadoop.hbase.master.ClusterStatusPublisher$MulticastPublisher
</value>
<description>
Implementation of the status publication with a multicast message.
</description>
</property>
<property>
<name>hbase.status.listener.class</name>
<value>org.apache.hadoop.hbase.client.ClusterStatusListener$MulticastListener
</value>
<description>
Implementation of the status listener with a multicast message.
</description>
</property>
<property>
<name>hbase.status.multicast.address.ip</name>
<value>226.1.1.3</value>
<description>
Multicast address to use for the status publication by multicast.
</description>
</property>
<property>
<name>hbase.status.multicast.address.port</name>
<value>16100</value>
<description>
Multicast port to use for the status publication by multicast.
</description>
</property>
<property>
<name>hbase.dynamic.jars.dir</name>
<value>${hbase.rootdir}/lib</value>
<description>
The directory from which the custom filter/co-processor 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.
</description>
</property>
<property>
<name>hbase.security.authentication</name>
<value>simple</value>
<description>
Controls whether or not secure authentication is enabled for HBase.
Possible values are 'simple' (no authentication), and 'kerberos'.
</description>
</property>
<property>
<name>hbase.rest.filter.classes</name>
<value>org.apache.hadoop.hbase.rest.filter.GzipFilter</value>
<description>
Servlet filters for REST service.
</description>
</property>
<property>
<name>hbase.master.loadbalancer.class</name>
<value>org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer
</value>
<description>
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).
</description>
</property>
<property>
<name>hbase.security.exec.permission.checks</name>
<value>false</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.procedure.regionserver.classes</name>
<value></value>
<description>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.
</description>
</property>
<property>
<name>hbase.procedure.master.classes</name>
<value></value>
<description>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.
</description>
</property>
<property>
<name>hbase.coordinated.state.manager.class</name>
<value>org.apache.hadoop.hbase.coordination.ZkCoordinatedStateManager
</value>
<description>Fully qualified name of class implementing coordinated
state manager.</description>
</property>
<property>
<name>hbase.regionserver.storefile.refresh.period</name>
<value>0</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.region.replica.replication.enabled</name>
<value>false</value>
<description>
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 mutatations 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 ReplicationAdmin java
class.
Replication to secondary region replicas works over standard inter-cluster
replication.
So replication, if disabled explicitly, also has to be enabled by
setting "hbase.replication"
to true for this feature to work.
</description>
</property>
<property>
<name>hbase.http.filter.initializers</name>
<value>org.apache.hadoop.hbase.http.lib.StaticUserWebFilter</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.security.visibility.mutations.checkauths</name>
<value>false</value>
<description>
This property if enabled, will check whether the labels in the visibility
expression are associated
with the user issuing the mutation
</description>
</property>
<property>
<name>hbase.http.max.threads</name>
<value>10</value>
<description>
The maximum number of threads that the HTTP Server will create in its
ThreadPool.
</description>
</property>
<property>
<name>hbase.replication.rpc.codec</name>
<value>org.apache.hadoop.hbase.codec.KeyValueCodecWithTags</value>
<description>
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.
</description>
</property>
<property>
<name>hbase.replication.source.maxthreads</name>
<value>10</value>
<description>
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.
</description>
</property>
<!-- Static Web User Filter properties. -->
<property>
<description>
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).
</description>
<name>hbase.http.staticuser.user</name>
<value>dr.stack</value>
</property>
<property>
<name>hbase.master.normalizer.class</name>
<value>org.apache.hadoop.hbase.master.normalizer.SimpleRegionNormalizer
</value>
<description>
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
</description>
</property>
<property>
<name>hbase.regionserver.handler.abort.on.error.percent</name>
<value>0.5</value>
<description>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.
</description>
</property>
<property>
<name>hbase.snapshot.master.timeout.millis</name>
<value>300000</value>
<description>
Timeout for master for the snapshot procedure execution
</description>
</property>
<property>
<name>hbase.snapshot.region.timeout</name>
<value>300000</value>
<description>
Timeout for regionservers to keep threads in snapshot request pool waiting
</description>
</property>
</configuration>
