Thanks!! Eric Stevens for your reply. We have following JVM settings :- --------------------------------------------- *memtable_offheap_space_in_mb: 15360 (*found in casandra.yaml *)* *MAX_HEAP_SIZE="16G" (*found in cassandra-env.sh *)*---------------------------------------------
And I also found big GC in log. But messages and big GC were logged at different-different time in system.log. I was expecting to happen them at same time after reading your reply. I also manually triggered GC but messages were not dropped. is *TRACE message drop *harmful or it's okay we can neglect them? Thank you!! On Wed, Jun 15, 2016 at 8:45 PM, Eric Stevens <migh...@gmail.com> wrote: > This is better kept to the User groups. > > What are your JVM memory settings for Cassandra, and have you seen big > GC's in your logs? > > The reason I ask is because that's a large number of column families, > which produces memory pressure, and at first blush that strikes me as a > likely cause. > > > On Wed, Jun 15, 2016 at 3:23 AM Varun Barala <varunbaral...@gmail.com> > wrote: > >> Hi all, >> >> Can anyone tell me that what are all possible reasons for below log:- >> >> >> *"INFO [ScheduledTasks:1] 2016-06-14 06:27:39,498 >> MessagingService.java:929 - _TRACE messages were dropped in last 5000 ms: >> 928 for internal timeout and 0 for cross node timeout".* >> I searched online for the same and found some reasons like:- >> >> * Disk is not able to keep up with your ingest >> * Resources are not able to support all parallel running tasks >> * If other nodes are down then due to large hint replay >> * Heavy workload >> >> But in this case other kind of messages (mutation, read, write etc) >> should be dropped by *C** but It doesn't happen. >> >> ----------------------------- >> Cluster Specifications >> ------------------------------ >> number of nodes = 1 >> total number of CF = 2000 >> >> ----------------------------- >> Machine Specifications >> ------------------------------ >> RAM 30 GB >> hard disk SSD >> ubuntu 14.04 >> >> >> Thanks in advance!! >> >> Regards, >> Varun Barala >> >
