Greg Smith wrote:
Yeah - with 64K chunksize I'm seeing a result more congruent with
yours (866 or so for 24 clients)
That's good to hear. If adjusting that helped so much, you might
consider aligning the filesystem partitions to the chunk size too; the
partition header usually screws that up on Linux. See these two
references for ideas:
http://www.vmware.com/resources/techresources/608
http://spiralbound.net/2008/06/09/creating-linux-partitions-for-clariion
Well I went away and did this (actually organized for for the system
folks to...). Retesting showed no appreciable difference (if anything
slower). Then I got to thinking:
For a partition created on a (hardware) raided device, sure - alignment
is very important, however in my case we are using software (md) raid -
which creates devices out of individual partitions (which are on
individual SAS disks) e.g:
md3 : active raid10 sda4[0] sdd4[3] sdc4[2] sdb4[1]
177389056 blocks 256K chunks 2 near-copies [4/4] [UUUU]
I'm thinking that alignment issues do not apply here, as md will
allocate chunks starting at the beginning of wherever sda4 (etc) begins
- so the absolute starting position of sda4 is irrelevant. Or am I
missing something?
Thanks again
Mark
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