Jay, I believe that compaction occurs on the data directories and not in the commitlog.
http://wiki.apache.org/cassandra/MemtableSSTable On Wed, Apr 17, 2013 at 7:58 PM, Jay Svc <jaytechg...@gmail.com> wrote: > Hi Alexis, > > Thank you for your response. > > My commit log is on SSD. which shows me 30 to 40 ms of disk latency. > > When I ran iostat; I see "await" 26ms to 30 ms for my commit log disk. My > CPU is less than 18% used. > > How I reduce the disk latency for my commit log disk. They are SSDs. > > Thank you in advance, > Jay > > > On Wed, Apr 17, 2013 at 3:58 PM, Alexis Rodríguez < > arodrig...@inconcertcc.com> wrote: > >> :D >> >> Jay, check if your disk(s) utilization allows you to change the >> configuration the way Edward suggest. iostat -xkcd 1 will show you how much >> of your disk(s) are in use. >> >> >> >> >> On Wed, Apr 17, 2013 at 5:26 PM, Edward Capriolo >> <edlinuxg...@gmail.com>wrote: >> >>> three things: >>> 1) compaction throughput is fairly low (yaml nodetool) >>> 2) concurrent compactions is fairly low (yaml) >>> 3) multithreaded compaction might be off in your version >>> >>> Try raising these things. Otherwise consider option 4. >>> >>> 4)$$$$$$$$$$$$$$$$$$$$$$$ RAID,RAM<CPU$$$$$$$$$$$$$$ >>> >>> >>> On Wed, Apr 17, 2013 at 4:01 PM, Jay Svc <jaytechg...@gmail.com> wrote: >>> >>>> Hi Team, >>>> >>>> >>>> >>>> I have a high write traffic to my Cassandra cluster. I experience a >>>> very high number of pending compactions. As I expect higher writes, The >>>> pending compactions keep increasing. Even when I stop my writes it takes >>>> several hours to finishing pending compactions. >>>> >>>> >>>> My CF is configured with LCS, with sstable_size_mb=20M. My CPU is below >>>> 20%, JVM memory usage is between 45%-55%. I am using Cassandra 1.1.9. >>>> >>>> >>>> How can I increase the compaction rate so it will run bit faster to >>>> match my write speed? >>>> >>>> >>>> Your inputs are appreciated. >>>> >>>> >>>> Thanks, >>>> >>>> Jay >>>> >>>> >>> >> >
