Thanks Dave. I've been using Cassandra, so I'm trying to get my head around the configuration/operational differences with ZK. You state that using 4 would actually decrease my reliability. Can you explain that further? I was under the impression that a 4th node would act as a non voting read only node until one of the other 3 fails. I thought that this extra node would give me some breathing room by allowing any node to fail and still have 3 voting nodes. Is this not the case?
Thanks, Todd On Wed, 2010-08-25 at 21:13 -0600, Ted Dunning wrote: > Just use 3 nodes. Life will be better. > > > > You can configure the fourth node in the event of one of the first > three failing and bring it on line. Then you can re-configure and > restart each of the others one at a time. This gives you flexibility > because you have 4 nodes, but doesn't decrease your reliability the > way that using a four node cluster would. If you need to do > maintenance on one node, just configure that node out as if it had > failed. > > > On Wed, Aug 25, 2010 at 4:26 PM, Dave Wright <wrig...@gmail.com> > wrote: > > You can certainly serve more reads with a 4th node, but I'm > not sure > what you mean by "it won't have a voting role". It still > participates > in voting for leaders as do all non-observers regardless of > whether it > is an even or odd number. With zookeeper there is no voting on > each > transaction, only leader changes. > > -Dave Wright > > > > On Wed, Aug 25, 2010 at 6:22 PM, Todd Nine > <t...@spidertracks.co.nz> wrote: > > Do I get any read performance increase (similar to an > observer) since > > the node will not have a voting role? > > > > > > > >