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> > KDM> The best stress test I have found has been to just do a single sequential > KDM> write stream with ZFS. i.e.: > KDM> > KDM> cd /path/to/zfs/pool > KDM> dd if=/dev/zero of=foo bs=1M > KDM> > 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 j...@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP 4BD6C0CB | _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"