Cody Yellan wrote:
You are right, Richard. RHEL5 had a stripe_cache_size of 256 when
the reshape began. I increased it to 1024 and the reshape speed
doubled to 4500K/s. I did not see any increase in memory usage. I
tried 2048 and then 4096 but saw no difference in speed.
Sorry, I did not make myself clear.
Back when I was seeing the slow resync speeds, it was due to larger than
default stripe_cache_size - I had increased to 16384.
When this was reduced back to the default, which I suspect is 256,
speeds were back up to more normal levels - much faster than the 4.5MB/s
you are seeing.
At some point, this issue was fixed and currently on 2.6.22, with a
stripe_cache_size of 16384 and a 4 x 500GB SATA II md RAID 5, resync
speed is 162MB/s.
Perhaps somthing different occurs on a reshape, (which I have only now
realised you were doing).
Regards,
Richard
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