> Date: Fri, 18 Feb 2011 15:13:06 -0800 > From: Jeremy Chadwick <[email protected]> > Sender: [email protected] > > 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++.
When FreeBSD updated its random number engine a couple of years ago, random and urandom became the same thing. Unless I am missing something, a switch should make no difference. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: [email protected] Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[email protected]"
