Thanks Camille, Sorry, my assumption was wrong. I've made now a test and indeed the session doesn't expire in this case. This means than the only problem is that the service is down for an increasing amount of time if snapshot is increasing. We use SAN to store the snapshot and reading it back twice during leader election can be a little slow (~30 secs). It is not bad at all but still have anybody tried making the leader election faster in this case?
Regards, Botond On Mon, Dec 12, 2011 at 18:35, Camille Fournier <[email protected]> wrote: > Existing sessions will not expire from the server side during election. > Your client code may choose to close them on its end if you sit in a > DISCONNECTED state for too long, but nothing should be expiring the > sessions while quorum is not available. > > C > > On Mon, Dec 12, 2011 at 12:06 PM, Botond Hejj <[email protected] >> wrote: > >> Hi ZooKeeper users, >> >> I am playing currently with zookeeper and testing what happens if the >> leader of an ensemble goes down. >> I know that during the leader election zookeeper server won't reply to >> any requests and if leader election takes a long time than existing >> sessions might expire. >> What I see in my tests that each server reads the last snapshot file >> to get last zxid for leader election and when the leader is elected >> than the leader reads the snapshot again before it syncs the >> followers. >> >> This means that the more data we store in zookeeper the longer it >> takes to elect a new leader. This is also means as load of the >> ensemble increases clients need bigger session timeout to "survive" >> the loss of the leader. >> >> Is it possible to do anything about this and have a fast leader >> election even if the snapshot is big? >> >> Regards, >> Botond Hejj >> -- Botond Hejj Morgan Stanley | Technology Lechner Odon fasor 8 | Floor 07 Budapest, 1095 Phone: +36 1 881-3962 [email protected]
