Index: hbase-common/src/main/resources/hbase-default.xml
===================================================================
--- hbase-common/src/main/resources/hbase-default.xml (revision 1511512)
+++ hbase-common/src/main/resources/hbase-default.xml (working copy)
@@ -283,12 +283,16 @@
zookeeper.session.timeout
90000
- ZooKeeper session timeout.
- HBase passes this to the zk quorum as suggested maximum time for a
- session (This setting becomes zookeeper's 'maxSessionTimeout'). See
- http://hadoop.apache.org/zookeeper/docs/current/zookeeperProgrammers.html#ch_zkSessions
- "The client sends a requested timeout, the server responds with the
- timeout that it can give the client. " In milliseconds.
+ 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.
+
zookeeper.znode.parent