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From Brian Tarbox <tar...@cabotresearch.com>
Subject puzzled why my cluster is slowing down
Date Mon, 07 Jan 2013 14:39:17 GMT
I have a 4 node cluster with lots JVM memory and lots of system memory that
slows down when I'm doing lots of writes.

Running DataStax charts I see my read and write latency rise from 50-100
u-secs to 1500-4500 u-secs.  This is across a 12 hour data load during
which time the applied load is high but fairly constant (500-700
writes/sec).

I'm trying to understand the slowdown: there is no memory pressure, I've
run every option under nodetool to look for bottlenecks (tpstats,
compactionStats, etc) and see none.  I'm running with keycache and have
about 98% hits.

What can I check next?
Thanks!

Brian Tarbox

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