mps(4) driver (LSI 6Gb SAS) commited to stable/8
freebsd at jdc.parodius.com
Fri Feb 18 23:13:09 UTC 2011
On Sat, Feb 19, 2011 at 02:05:33AM +0300, Dmitry Morozovsky wrote:
> On Fri, 18 Feb 2011, Kenneth D. Merry wrote:
> KDM> > KDM> I just merged the mps(4) driver to stable/8, for those of you with LSI 6Gb
> KDM> > KDM> SAS hardware.
> KDM> >
> KDM> > [snip]
> KDM> >
> KDM> > Again, thank you very much Ken. I'm planning to stress test this on 846 case
> KDM> > filled with 12 (yet) WD RE4 disks organized as raidz2, and will post the
> KDM> > results.
> KDM> >
> KDM> > Any hints to particularly I/O stressing patterns? Out of my mind, I'm planning
> KDM> > multiple parallel -j'ed builds, parallel tars, *SQL benchmarks -- what else
> KDM> > could you suppose?
> KDM> The best stress test I have found has been to just do a single sequential
> KDM> write stream with ZFS. i.e.:
> KDM> cd /path/to/zfs/pool
> KDM> dd if=/dev/zero of=foo bs=1M
> KDM> Just let it run for a long period of time and see what happens.
> Well, provided that I'm plannign to use ZFSv28 to be in place, wouldn't be
> /dev/random more appropriate?
No -- /dev/urandom maybe, but not /dev/random. /dev/urandom will also
induce significantly higher CPU load than /dev/zero will. Don't forget
that ZFS is a processor-centric (read: no offloading) system.
I tend to try different block sizes (starting at bs=8k and working up to
bs=256k) for sequential benchmarks. The "sweet spot" on most disks I've
found is 64k. Otherwise use benchmarks/bonnie++.
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP 4BD6C0CB |
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