Date: Fri, 18 Feb 2011 15:13:06 -0800 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Dmitry Morozovsky <marck@rinet.ru> Cc: freebsd-scsi@freebsd.org, stable@freebsd.org, "Kenneth D. Merry" <ken@freebsd.org> Subject: Re: mps(4) driver (LSI 6Gb SAS) commited to stable/8 Message-ID: <20110218231306.GA69028@icarus.home.lan> In-Reply-To: <alpine.BSF.2.00.1102190203470.14809@woozle.rinet.ru> References: <20110218164209.GA77903@nargothrond.kdm.org> <alpine.BSF.2.00.1102190104280.14809@woozle.rinet.ru> <20110218225204.GA84087@nargothrond.kdm.org> <alpine.BSF.2.00.1102190203470.14809@woozle.rinet.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
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 jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP 4BD6C0CB |
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110218231306.GA69028>