There is 1-4 compactions at that moment. We have many tombstones, which does not removed. DroppableTombstoneRatio is 5-6 (greater than 1)
> On 12 Feb 2016, at 15:53, Julien Anguenot <jul...@anguenot.org> wrote: > > Hey, > > What about compactions count when that is happening? > > J. > > >> On Feb 12, 2016, at 3:06 AM, Skvazh Roman <r...@skvazh.com> wrote: >> >> Hello! >> We have a cluster of 25 c3.4xlarge nodes (16 cores, 32 GiB) with attached >> 1.5 TB 4000 PIOPS EBS drive. >> Sometimes one or two nodes user cpu spikes to 100%, load average to 20-30 - >> read requests drops of. >> Only restart of this cassandra services helps. >> Please advice. >> >> One big table with wide rows. 600 Gb per node. >> LZ4Compressor >> LeveledCompaction >> >> concurrent compactors: 4 >> compactor throughput: tried from 16 to 128 >> Concurrent_readers: from 16 to 32 >> Concurrent_writers: 128 >> >> >> https://gist.github.com/rskvazh/de916327779b98a437a6 >> >> >> JvmTop 0.8.0 alpha - 06:51:10, amd64, 16 cpus, Linux 3.14.44-3, load avg >> 19.35 >> http://code.google.com/p/jvmtop >> >> Profiling PID 9256: org.apache.cassandra.service.CassandraDa >> >> 95.73% ( 4.31s) >> ....google.common.collect.AbstractIterator.tryToComputeN() >> 1.39% ( 0.06s) com.google.common.base.Objects.hashCode() >> 1.26% ( 0.06s) io.netty.channel.epoll.Native.epollWait() >> 0.85% ( 0.04s) net.jpountz.lz4.LZ4JNI.LZ4_compress_limitedOutput() >> 0.46% ( 0.02s) net.jpountz.lz4.LZ4JNI.LZ4_decompress_fast() >> 0.26% ( 0.01s) com.google.common.collect.Iterators$7.computeNext() >> 0.06% ( 0.00s) io.netty.channel.epoll.Native.eventFdWrite() >> >> >> ttop: >> >> 2016-02-12T08:20:25.605+0000 Process summary >> process cpu=1565.15% >> application cpu=1314.48% (user=1354.48% sys=-40.00%) >> other: cpu=250.67% >> heap allocation rate 146mb/s >> [000405] user=76.25% sys=-0.54% alloc= 0b/s - SharedPool-Worker-9 >> [000457] user=75.54% sys=-1.26% alloc= 0b/s - SharedPool-Worker-14 >> [000451] user=73.52% sys= 0.29% alloc= 0b/s - SharedPool-Worker-16 >> [000311] user=76.45% sys=-2.99% alloc= 0b/s - SharedPool-Worker-4 >> [000389] user=70.69% sys= 2.62% alloc= 0b/s - SharedPool-Worker-6 >> [000388] user=86.95% sys=-14.28% alloc= 0b/s - SharedPool-Worker-5 >> [000404] user=70.69% sys= 0.10% alloc= 0b/s - SharedPool-Worker-8 >> [000390] user=72.61% sys=-1.82% alloc= 0b/s - SharedPool-Worker-7 >> [000255] user=87.86% sys=-17.87% alloc= 0b/s - SharedPool-Worker-1 >> [000444] user=72.21% sys=-2.30% alloc= 0b/s - SharedPool-Worker-12 >> [000310] user=71.50% sys=-2.31% alloc= 0b/s - SharedPool-Worker-3 >> [000445] user=69.68% sys=-0.83% alloc= 0b/s - SharedPool-Worker-13 >> [000406] user=72.61% sys=-4.40% alloc= 0b/s - SharedPool-Worker-10 >> [000446] user=69.78% sys=-1.65% alloc= 0b/s - SharedPool-Worker-11 >> [000452] user=66.86% sys= 0.22% alloc= 0b/s - SharedPool-Worker-15 >> [000256] user=69.08% sys=-2.42% alloc= 0b/s - SharedPool-Worker-2 >> [004496] user=29.99% sys= 0.59% alloc= 30mb/s - CompactionExecutor:15 >> [004906] user=29.49% sys= 0.74% alloc= 39mb/s - CompactionExecutor:16 >> [010143] user=28.58% sys= 0.25% alloc= 26mb/s - CompactionExecutor:17 >> [000785] user=27.87% sys= 0.70% alloc= 38mb/s - CompactionExecutor:12 >> [012723] user= 9.09% sys= 2.46% alloc= 2977kb/s - RMI TCP >> Connection(2673)-127.0.0.1 >> [000555] user= 5.35% sys=-0.08% alloc= 474kb/s - SharedPool-Worker-24 >> [000560] user= 3.94% sys= 0.07% alloc= 434kb/s - SharedPool-Worker-22 >> [000557] user= 3.94% sys=-0.17% alloc= 339kb/s - SharedPool-Worker-25 >> [000447] user= 2.73% sys= 0.60% alloc= 436kb/s - SharedPool-Worker-19 >> [000563] user= 3.33% sys=-0.04% alloc= 460kb/s - SharedPool-Worker-20 >> [000448] user= 2.73% sys= 0.27% alloc= 414kb/s - SharedPool-Worker-21 >> [000554] user= 1.72% sys= 0.70% alloc= 232kb/s - SharedPool-Worker-26 >> [000558] user= 1.41% sys= 0.39% alloc= 213kb/s - SharedPool-Worker-23 >> [000450] user= 1.41% sys=-0.03% alloc= 158kb/s - SharedPool-Worker-17 >
