On 06/28/2012 08:21 AM, Stefan Priebe - Profihost AG wrote:
Am 27.06.2012 18:00, schrieb Mark Nelson:
On 06/27/2012 10:28 AM, Stefan Priebe wrote:
Well, as we said, 1GHz/OSD was a WAG (wild-ass guess), but 3.6GHz+/OSD
is farther outside of that range than I would have expected. It might
just be a consequence of using SSDs, since they can sustain so much
more
throughput.
Sure it was just so much away from 1Ghz that i wanted to ask.
What is the cluster doing when you see those CPU usage numbers?
random write I/O from one KVM. 14k I/Ops with random 4k writes.
Stefan
I think I was seeing about 80-85% CPU utilization with 5 SSD OSDs on our
6-core AMD nodes, but I was just doing sequential writes with rados
bench.
While doing sequential writes i see pretty low CPU usage. Random writes
is the problem.
Stefan
It would be interesting to see where all your CPU time is being spent.
What benchmark are you using to do the random writes?
Mark
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