I was under the impression that there was some persistent data kept in ZK by hbase, good to know. Perhaps a FAQ entry for this?
Patrick On Fri, Jul 22, 2011 at 10:42 PM, Andrew Purtell <[email protected]> wrote: > 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 >> >
