Hi Xiang, It's not the root cause, if you skim through sendBuffer impl in NIOServerCnxn.java, you'll find there's a catch statement finally to log all exception, no throw again.
IMHO, the hbase master log file is the right place you need to dive:) ________________________________________ 发件人: Xiang Hua [bea...@gmail.com] 发送时间: 2012年10月12日 3:14 收件人: user@hbase.apache.org 主题: hmaster down cause by zookeeper? Hi, we using CDH3, using zookeeper,hdfs and hbase. now 2 hmaster is down, we find some error message from zookeeper, see below: 2012-10-12 02:02:53,928 - ERROR [CommitProcessor:1:NIOServerCnxn@445 ] - Unexpected Exception: java.nio.channels.CancelledKeyException at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:73) at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:77) at org.apache.zookeeper.server.NIOServerCnxn.sendBuffer(NIOServerCnxn.java:418) at org.apache.zookeeper.server.NIOServerCnxn.sendResponse(NIOServerCnxn.java:1509) at org.apache.zookeeper.server.FinalRequestProcessor.processRequest(FinalRequestProcessor.java:367) at org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:73) 2012-10-12 02:02:53,928 - ERROR [CommitProcessor:1:NIOServerCnxn@445 ] - Unexpected Exception: java.nio.channels.CancelledKeyException at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:73) at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:77) at org.apache.zookeeper.server.NIOServerCnxn.sendBuffer(NIOServerCnxn.java:418) at org.apache.zookeeper.server.NIOServerCnxn.sendResponse(NIOServerCnxn.java:1509) at org.apache.zookeeper.server.FinalRequestProcessor.processRequest(FinalRequestProcessor.java:367) at org.apache.zookeeper.server.quorum.CommitProcessor.run(CommitProcessor.java:73) 2:31:34 any reconmends? Thanks! beatls