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,JayOn Wed, Apr 17, 2013 at 3:58 PM, Alexis Rodríguez <firstname.lastname@example.org> wrote:
:DJay, 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 <email@example.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 versionTry raising these things. Otherwise consider option 4.4)$$$$$$$$$$$$$$$$$$$$$$$ RAID,RAM<CPU$$$$$$$$$$$$$$On Wed, Apr 17, 2013 at 4:01 PM, Jay Svc <firstname.lastname@example.org> wrote:
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.