On 02/06/2012 10:22 AM, Yehuda Sadeh Weinraub wrote:
On Mon, Feb 6, 2012 at 8:20 AM, Jim Schutt<jaschut@xxxxxxxxxx> wrote:
The above suggests to me that the slowdown is a result
of requests not getting submitted at the same rate as
when things are running well.
Yeah, it really looks like that. My suggestions wouldn't help there.
I do see that when things go well the number of writes per device is
capped at ~200 writes per second and the throughput per device is
~100MB/sec. Is 100MB/sec the expected device throughput?
Pretty much, at least for the outer tracks on a drive. I've seen
~108 MB/s with dd to a block device. Also, I've got 8 drives per
SAS adapter with 6 Gb/s links, so it seems unlikely to me that my
disk subsystem is any sort of significant bottleneck.
-- Jim
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