On Tue, 12 Jun 2007, Bill Davidsen wrote:
Dexter Filmore wrote:
I recently upgraded my file server, yet I'm still unsatisfied with the
write speed.
Machine now is a Athlon64 3400+ (Socket 754) equipped with 1GB of RAM.
The four RAID disks are attached to the board's onbaord sATA controller
(Sil3114 attached via PCI)
Kernel is 2.6.21.1, custom on Slackware 11.0.
RAID is on four Samsung SpinPoint disks, has LVM, 3 volumes atop of each
XFS.
The machine does some other work, too, but still I would have suspected to
get into the 20-30MB/s area. Too much asked for?
Increase your stripe cache size in /sys/block/mdX/md/stripe_cache_size. If
you have a chunk size of 256, try setting the cache size to 8192 and see if
your write performance ends up ~100MB/s or so.
echo 8192 > /sys/block/mdX/md/stripe_cache_size
Where "X" is your array name, of course.
Note, larger values will help more, but it's definitely diminishing returns,
so don't get carried away. There was a report of problems with size > 32768,
I don't remember the details, so I would avoid that as well.
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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I was the one who tried > 32768 it crashed the machine (on an older box).
Justin.
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