Hi Geoff, The default number of connections in ZK is 10 I believe. You don't need 32K for 100 mappers. But it would help to increase that. Here's my answer for a related problem http://stackoverflow.com/questions/6153560/hbase-client-connectionloss-for-hbase-error/
I'm not sure how HBase managed ZK works, but I suspect there's a single instance (somebody correct me if I'm wrong). There's a "zk dump" link on the HBase master web interface where you can see the status of all ZK connections to each node. You should run a ZK cluster as well on the HBase nodes (3 or 5 nodes, make sure it's not an even number). Here's a set of puppet recipes for Hadoop, HBase, Zookeeper https://github.com/hstack/puppet as well if you want to automate the setup. Cosmin On Jun 4, 2011, at 3:28 AM, Geoff Hendrey wrote: > Hi Folks - > > > > I am experiencing "ConnectionLoss for /hbase" when I run a mapreduce job > with around 100 mappers and TableInputFormat. I am running a fully > distributed cluster, letting hbase manage zookeeper. I am running HBase > 90.1. Is the solution, per this jira, > https://issues.apache.org/jira/browse/HBASE-3773 , to increase > hbase.zookeeper.property.maxClientCnxns to 32k? > > > > This is the stack trace that I get. > > > > Caused by: org.apache.hadoop.hbase.ZooKeeperConnectionException: > org.apache.hadoop.hbase.ZooKeeperConnectionException: > org.apache.zookeeper.KeeperException$ConnectionLossException: > KeeperErrorCode = ConnectionLoss for /hbase > > at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat > ion.getZooKeeperWatcher(HConnectionManager.java:988) > > at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat > ion.setupZookeeperTrackers(HConnectionManager.java:301) > > at > org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat > ion.<init>(HConnectionManager.java:292) > > at > org.apache.hadoop.hbase.client.HConnectionManager.getConnection(HConnect > ionManager.java:155) > > at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:167) > > at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:145) > > > > > > -geoff >
