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From OpenSource Dev <dev.opensou...@gmail.com>
Subject High cpu usage on a region server
Date Wed, 11 Sep 2013 20:49:33 GMT
Hi,

I'm using HBase 0.94.6 (CDH 4.3) for Opentsdb. So far I have had no
issues with writes/puts. System is handles upto 800k puts per seconds
without issue. On average we do 250k puts per second.

I am having the problem with Reads, I've also isolated where the
problem is but not been able to find the root cause.

I have 16 machines running hbase-region server, each has ~35 regions.
Once in a while cpu goes flatout 80% in 1 region server. These are the
things i've noticed in ganglia:

hbase.regionserver.request - evenly distributed. Not seeing any spikes
on the busy server
hbase.regionserver.blockCacheSize - between 500MB and 1000MB
hbase.regionserver.compactionQueueSize - avg 2 or less
hbase.regionserver.blockCacheHitRatio - 30% on busy node, >60% on other nodes


JVM Heap size is set to 16GB and I'm using -XX:+UseParNewGC
-XX:+UseConcMarkSweepGC

I've noticed the system load moves to a different region, sometimes
within a minute, if the busy region is restarted.

Any suggestion what could be causing the load and/or what other
metrics should I check ?


Thank you!

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