You are right, it looks like I am doing a lot of GC. Is there any short-term solution for this other than bumping up the heap ? because, even if I increase the heap I will run into the same issue. Only the time before I hit OOM will be lengthened.
It will be while before we go to latest and greatest Cassandra. Thanks ! On Thu, May 30, 2013 at 12:05 AM, Jonathan Ellis <jbel...@gmail.com> wrote: > Sounds like you're spending all your time in GC, which you can verify > by checking what GCInspector and StatusLogger say in the log. > > Fix is increase your heap size or upgrade to 1.2: > http://www.datastax.com/dev/blog/performance-improvements-in-cassandra-1-2 > > On Wed, May 29, 2013 at 11:32 PM, srmore <comom...@gmail.com> wrote: > > Hello, > > I am observing that my performance is drastically decreasing when my data > > size grows. I have a 3 node cluster with 64 GB of ram and my data size is > > around 400GB on all the nodes. I also see that when I re-start Cassandra > the > > performance goes back to normal and then again starts decreasing after > some > > time. > > > > Some hunting landed me to this page > > http://wiki.apache.org/cassandra/LargeDataSetConsiderations which talks > > about the large data sets and explains that it might be because I am > going > > through multiple layers of OS cache, but does not tell me how to tune it. > > > > So, my question is, are there any optimizations that I can do to handle > > these large datatasets ? > > > > and why does my performance go back to normal when I restart Cassandra ? > > > > Thanks ! > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder, http://www.datastax.com > @spyced >
