Dissapointing performance of ciss RAID 0+1 ?
markir at paradise.net.nz
Thu Nov 9 23:09:47 UTC 2006
Pete French wrote:
>> You might be able to speed up the read by playing with the vfs.read_max
>> sysctl (try 16 or 32).
> Wow! That makes a huge difference, thanks. Should this not be in 'man tuning' ?
Yeah, I believe I've seen it mentioned *somewhere* with respect to
working with RAID (of course, I can't find it now....).
The other thing you might find useful for improving sequential
performance is using newfs options '-b 32768 -f 4096' - I've found it
produces a noticeable performance improvement (can't recall exactly but
in the region of 10%).
I'm using an older system (3ware 7506 + 4 7200 rpm disks RAID 0 256 K
stripe), and with the above newfs settings + vfs.read_max=16 I get about
190Mb/s for 8k reads and 160Mb/s for 8k writes (sustained for quite big
files e.g. 16Gb). This is on 6.2 PRERELEASE, and I'm pretty happy with
that level of performance (nice job to those of you who have been
steadily making 6-STABLE go faster....)!
More information about the freebsd-stable