HBase does not keep any persistent state in ZooKeeper. You can restart your ZK cluster one peer at a time without affecting HBase.
If you are going to bring your entire ZK cluster down, first shut down HBase. Then once ZK is started again, bring up HBase. - Andy Problems worthy of attack prove their worth by hitting back. - Piet Hein (via Tom White) ----- Original Message ----- > From: Patrick Hunt <[email protected]> > To: [email protected] > Cc: > Sent: Thursday, July 21, 2011 3:56 PM > Subject: Re: Zookeeper/Hbase storage type on EC2 > > On Thu, Jul 21, 2011 at 1:21 AM, Yves Langisch <[email protected]> wrote: >> I just need a statement if it makes sense to use ephemeral storage for ZK > at >> all (in conjunction with Hbase if the answer depends on the use case)? >> >> Any help is appreciated. >> >> >> On 19.07.2011 19:37, Yves Langisch wrote: > >>> I plan to setup a HBase installation on EC2. As recommended I therefore >>> want to setup a zookeeper ensemble with 3 nodes but I'm not sure > what kind >>> of storage I've to choose for the two zk directories (dataDir and >>> dataLogDir). Do this two directories need to be on a persistent storage >>> which survives a node crash? Or does an ephemeral storage device > suffice >>> since a failed node which is restarted is being synchronized with the > other >>> two nodes anyway? And what happens when I restart the whole zk ensemble > with >>> ephemeral storage which means there is no zk data available anymore > after >>> booting up? Any impact on the Hbase cluster? > > I don't think you want to use ephemeral storage given that HBase would > lose information if the zk cluster was restarted. But really that's a > better question for the hbase team, I don't know exactly how they are > using ZK and the effects of such a loss on their application. > > Regards, > > Patrick >
