It's unlikely that HH is the issue. (Disclaimer, am not familiar with HH in 1.0, i know it's changes a bit)
Take a look at the TP Stats, what's happening ? Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/10/2011, at 10:10 AM, Jérémy SEVELLEC wrote: > Ok. > > I think a degration could be normal because your cluster is in a degraded > state when a node is down. > > With a replication_factor of 3 and with a 3 nodes cluster, each data you > write is replicated on each node. As One node is down, when writing, it's > impossible to send a replica on the down node and hints are send : > http://www.datastax.com/docs/1.0/dml/about_writes#hinted-handoff-writes > And it could be more expensive to achieve QUORUM when you read in that > context. > > It may be one explanation. You can turn cassandra log into debug level to see > what happen when when there is a down node. > > 2011/10/19 Yang <teddyyyy...@gmail.com> > 3 > > sorry forgot this important info > > On Oct 19, 2011 11:31 AM, "Jérémy SEVELLEC" <jsevel...@gmail.com> wrote: > Hi, what is your replication_factor? > > 2011/10/19 Yang <teddyyyy...@gmail.com> > I'm using a cassandra version compiled from 1.0.0 github HEAD. > > I have 3 nodes, A B and C, on node A I run a client, which talks only > to B as the coordinator. > > the performance is pretty good, a QUORUM read+write takes < 10ms. > > but then I shutdown C, quickly the performance starts to degrade, and > QUORUM read+write time steadily increase to about 300ms. > > if I shutdown A and keep C, I observe the same effect. > > > I understand that "2 out of 3" is going to give you faster response > than "2 out of 2", but the difference should not be that dramatic as > 10ms vs 300ms. > > any possible reasons for this?(or how to debug this?) > > Thanks > Yang > > > > -- > Jérémy > > > > -- > Jérémy
