HBase Log Split 配置相关
（1）HMaster?SplitLogManager
? ? // get a list for previously failed RS which need log splitting work
? ? // we recover hbase:meta region servers inside master initialization and
? ? // handle other failed servers in SSH in order to start up master node ASAP
? ? Set<ServerName> previouslyFailedServers = this.fileSystemManager
? ? ? ? .getFailedServersFromLogFolders();
? ?LogSplit工作经由SSH（ServerShutdownHandler）触发，
? ?M_SERVER_SHUTDOWN ? ? ? ? (70, ExecutorType.MASTER_SERVER_OPERATIONS)
? ?this.executorService.startExecutorService(ExecutorType.MASTER_SERVER_OPERATIONS,
? ? ? conf.getInt("hbase.master.executor.serverops.threads", 5));
? ?HMaster每次最多处理?hbase.master.executor.serverops.threads 这么多个SSH，如果启动时有大量的异常Server需要处理时，可以调大这个参数。
?
（2）HRegionServer ?SplitLogWorker
? ??https://issues.apache.org/jira/browse/HBASE-9736
? ? this.maxConcurrentTasks =
? ? ? ? conf.getInt("hbase.regionserver.wal.max.splitters", DEFAULT_MAX_SPLITTERS);
? ?同时可以获取多个Task来处理。一个Task实际对应一个HLog文件。
?
