为什么给HBase使用的HDFS目录设置quota会造成HBase故障

问题

为什么给HDFS上的HBase使用的目录设置quota会造成HBase故障？

回答

表的flush操作是在HDFS中写MemStore数据。

如果HDFS目录没有足够的磁盘空间quota，flush操作会失败，这样region server将会终止。

Caused by: org.apache.hadoop.hdfs.protocol.DSQuotaExceededException: The DiskSpace quota of /hbase/data/<namespace>/<tableName> is exceeded: quota = 1024 B = 1 KB but diskspace consumed = 402655638 B = 384.00 MB
?at org.apache.hadoop.hdfs.server.namenode.DirectoryWithQuotaFeature.verifyStoragespaceQuota(DirectoryWithQuotaFeature.java:211)
?at org.apache.hadoop.hdfs.server.namenode.DirectoryWithQuotaFeature.verifyQuota(DirectoryWithQuotaFeature.java:239)
?at org.apache.hadoop.hdfs.server.namenode.FSDirectory.verifyQuota(FSDirectory.java:882)
?at org.apache.hadoop.hdfs.server.namenode.FSDirectory.updateCount(FSDirectory.java:711)
?at org.apache.hadoop.hdfs.server.namenode.FSDirectory.updateCount(FSDirectory.java:670)
?at org.apache.hadoop.hdfs.server.namenode.FSDirectory.addBlock(FSDirectory.java:495)

上述异常中，表“/hbase/data/<namespace>/<tableName>”的磁盘空间quota值为1KB，但是MemStore数据为384.00MB，所以flush操作失败并且region server会终止。

在region server终止时，HMaster对终止的region server的WAL文件进行replay操作以恢复数据。由于限制了磁盘空间quota值，导致WAL文件的replay操作失败进而导致HMaster进程异常退出。

2016-07-28 19:11:40,352 | FATAL | MASTER_SERVER_OPERATIONS-10-91-9-131:16000-0 | Caught throwable while processing event M_SERVER_SHUTDOWN | org.apache.hadoop.hbase.master.HMaster.abort(HMaster.java:2474)
java.io.IOException: failed log splitting for 10-91-9-131,16020,1469689987884, will retry
?at org.apache.hadoop.hbase.master.handler.ServerShutdownHandler.resubmit(ServerShutdownHandler.java:365)
?at org.apache.hadoop.hbase.master.handler.ServerShutdownHandler.process(ServerShutdownHandler.java:220)
?at org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:129)
?at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
?at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
?at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: error or interrupted while splitting logs in [hdfs://hacluster/hbase/WALs/<RS-Hostname>,<RS-Port>,<startcode>-splitting] Task = installed = 6 done = 3 error = 3
?at org.apache.hadoop.hbase.master.SplitLogManager.splitLogDistributed(SplitLogManager.java:290)
?at org.apache.hadoop.hbase.master.MasterFileSystem.splitLog(MasterFileSystem.java:402)
?at org.apache.hadoop.hbase.master.MasterFileSystem.splitLog(MasterFileSystem.java:375)

因此，不支持用户对HDFS上的HBase目录进行quota值设置。上述问题可通过下述步骤解决：