I don't think it is gc related issue. There is no correlation between gc times and the freeze times. More over I don't see any gc activity that lasts for omre than o.03 sec. But there is a correlation between disk flushing operations. I've noticed that the system freezes each time when my commit log reaches 1.1G. I have 1024M memtable size so I assume this is when the data flushing occurs.
On Thu, Feb 25, 2010 at 4:13 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > Then you should check GC timing with -Xverbose:gc option (see: > http://wiki.apache.org/cassandra/RunningCassandra for how to modify > jvm options) for a correlation. > > On Thu, Feb 25, 2010 at 8:09 AM, Boris Shulman <shulm...@gmail.com> wrote: >> In these tests I perform only write operations, no reads. >> >> On Thu, Feb 25, 2010 at 4:07 PM, Jonathan Ellis <jbel...@gmail.com> wrote: >>> The only kind of "freeze" that makes sense there is your reads are i/o >>> bound and the extra disk activity is killing you. In that case the >>> fix is to add more RAM, or give less to the JVM so the OS can use more >>> for buffer cache. >>> >>> On Thu, Feb 25, 2010 at 8:01 AM, Boris Shulman <shulm...@gmail.com> wrote: >>>> In my case the cassandra node freezes while memtable flush operation >>>> is performed or compactation operation is performed. How can I >>>> optimize the cassandra configuration in order to avoid this behavior? >>>> I've tried both using large memtable size (1G) and small (128M) but in >>>> every case I have some sort of freezes when the data is flushed to the >>>> disk. >>>> >>>> Please advice. >>>> >>> >> >
