This sounds similar to /proc/sys/vm/swappiness misconfiguration. Is it zero or close to zero? If setting it 0 solves your problem, make sure all your nodes get this:
/etc/sysctl.conf: vm.swappiness=0 On Wed, Apr 28, 2010 at 12:12 PM, Kyusik Chung <kyu...@discovereads.com>wrote: > Hello. I am using Cassandra 0.6.1 on ubuntu 8.04. 3 node cluster. > > I notice that when I start making lots of read requests (serially), memory > usage of jsvc keeps climbing until it uses up all memory on the server > (happens for all 3 servers in the cluster). At that point, the box starts > swapping a little (but not too much) and performance is degraded. Read > performance does not drop off a cliff, but it does take a serious hit (maybe > 50%). > > I have tried setting Xmx to various different values, but it doesnt seem to > limit the growth in memory usage. I understand that I should expect to see > jsvc use a bit more memory than what the jvm is configured to use, but it > doesnt seem to be limited to just an overhead. I have set Xmx all the way > down to 128M (just to test) and still jsvc will use up 2G of memory. > > Are there other settings that I should be changing? > > Note that when I test by simply running a lot of writes but no reads, jsvc > seems to respect the Xmx value. > > Thanks! > > Kyusik Chung -- timeless(ness)
