Hi! My answers are inline. On Mon, Feb 27, 2017 at 11:48 AM, Kant Kodali <k...@peernova.com> wrote:
> > > On Mon, Feb 27, 2017 at 10:30 AM, Romain Hardouin <romainh...@yahoo.fr> > wrote: > >> Hi, >> >> Regarding shared pool workers see CASSANDRA-11966. You may have to >> backport it depending on your Cassandra version. >> > > *we are currently using 3.0.9. should we use 3.8 or 3.10?* > >> >> Did you try to lower compaction throughput to see if it helps? Be sure to >> keep an eye on pending compactions, SSTables count and SSTable per read of >> course. >> > > *I haven't done any tuning yet. Can I change this on a running > instance? If so, how? or does it require a downtime?* > >> >> "alloc" is the memory allocation rate. You can see that compactions are >> GC intensive. >> > >> You won't be able to achieve impressive writes/s with LWT. But maybe >> there is room for improvement. Try GC tuning, different pool sizes for NTR, >> concurrent reads and writes, compaction executors, etc. Also check if you >> can improve network latency (e.g. VF or ENA on AWS). >> > > * GC seems to be fine because when I checked GC is about 0.25%. Total > GC time is about 6minutes since the node is up and running for about 50 > hours*. > >> >> What LWT rate would you want to achieve? *5000 is the target.* >> >> Best, >> >> Romain >> >> >> >> Le Lundi 27 février 2017 12h48, Kant Kodali <k...@peernova.com> a écrit : >> >> >> Also Attached is a flamed graph generated from a thread dump. >> >> On Mon, Feb 27, 2017 at 2:32 AM, Kant Kodali <k...@peernova.com> wrote: >> >> Hi, >> >> Attached are the stats of my Cassandra node running on a 4-core CPU. I am >> using sjk-plus tool for the first time so what are the things I should >> watched out for in my attached screenshot? I can see the CPU is almost >> maxed out but should I say that is because of compaction or >> shared-worker-pool threads (which btw, I dont know what they are doing >> perhaps I need to take threadump)? Also what is alloc for each thread? >> >> I have a insert heavy workload (almost like an ingest running against >> cassandra cluster) and in my case all writes are LWT. >> >> The current throughput is 1500 writes/sec where each write is about 1KB. >> How can I tune something for a higher throughput? Any pointers or >> suggestions would help. >> >> Thanks much, >> kant >> >> >> >> >> >
