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From Alain RODRIGUEZ <>
Subject Re: High disk read throughput on only one node.
Date Wed, 19 Dec 2012 22:30:22 GMT
"Is there a sustained difference or did it settle back ? "

Sustained, clearly. During the day all nodes read at about 6MB/s while this
one reads at 30-40 MB/s. At night while other reads 2MB/s the "broken"
nodes reads at 8-10MB/s

"Could this have been compaction or repair or upgrade tables working ? "

Was my first thought but definitely no. this occurs continuously.

"Do the read / write counts available in nodetool cfstats show anything
different ? "

The cfstats shows different counts (a lot less reads/writes for the "bad"
node)  but they didn't join the ring at the same time. I join you the
cfstats just in case it could help somehow.

Node  38: (bad one)
Node  32:
Node 154:


"clients always connect to that server"

I didn't join it in the screenshot from AWS console, but AWS report an
(almost) equal network within the nodes (same for output and cpu). The cpu
load is a lot higher in the broken node as shown by the OpsCenter, but
that's due to the high iowait...)

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