Yes you can do a rolling restart. For more info on the counters architecture see the presentation here http://www.datastax.com/events/cassandrasf2011/presentations
Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/12/2011, at 10:10 PM, Alain RODRIGUEZ wrote: > By the way, I wonder if a rolling restart is still possible when I am using > counters ? Don't we lose the SPOF too, considering that counters are wrong > every time we retry to write them with the client ? > > > 2011/12/16 Alain RODRIGUEZ <arodr...@gmail.com> > Can we have a hope that counters will be replayed as safely as a classical > data someday ? Do someone still work on jiras like > issues.apache.org/jira/browse/CASSANDRA-2495 ? I thought that replaying a > write from the client didn't lead to over-counts contrary to the internal > cassandra replay from commitlog. > > I just made a new connection pool with retries / 2 and timeouts * 4. I hope > it will improve the accuracy of my counters. > > Anyways, thank you for answering that fast. > > Alain > > 2011/12/16 Tyler Hobbs <ty...@datastax.com> > Probably quite a few of them are coming from automatic retries by phpcassa. > When working with counters, I recommend minimizing retries and/or increasing > timeouts. Usually this means you want to use a separate connection pool with > different settings just for counters. > > By the way, this advice applies to other clients as well. > > > On Wed, Dec 14, 2011 at 10:29 AM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > Hi everybody. > > I'm using a lot of counters to make statistics on a 4 nodes cluster (ec2 > m1.small) with phpcassa (cassandra v1.0.2). > > I store some events and increment counters at the same time. > > Counters give me over-counts compared with the count of every corresponding > events. > > I sure that my non-counters counts are good. > > I'm not sure why these over-counts happen, but I heard that recovering from > commitlogs can produce this. > I have some timeouts on phpcassa which are written in my apache logs while a > compaction is running. However I am always able to write at Quorum, so I > guess I shouldn't have to recover from cassandra commitlogs. > > Where can these over-counts come from ? > > Alain > > > > > -- > Tyler Hobbs > DataStax > > >
