Date: Wed, 17 Jun 2009 10:40:07 -0500 From: Joe Koberg <joe@osoft.us> To: Dan Naumov <dan.naumov@gmail.com> Cc: freebsd-fs@freebsd.org, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: ZFS performance on 7.2-release/amd64 low compared to UFS2 + SoftUpdates Message-ID: <4A390E57.9010701@osoft.us> In-Reply-To: <cf9b1ee00906170034q1cee4581hb518f53e9f368368@mail.gmail.com> References: <cf9b1ee00906170034q1cee4581hb518f53e9f368368@mail.gmail.com>
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The difference in layout can easily explain a 2x difference in sequential transfer performance. I seriously doubt your disk is really getting 23K seeks/s done in the UFS case - 100/s sounds much more reasonable for real hardware. Perhaps the results of caching? Joe Koberg Dan Naumov wrote: > I am wondering if the numbers I am seeing is something expected or is > something broken somewhere. Output of bonnie -s 1024: > > on UFS2 + SoftUpdates: > > -------Sequential Output-------- ---Sequential Input-- --Random-- > -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- > Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU > 1024 56431 94.5 88407 38.9 77357 53.3 64042 98.6 644511 98.6 23603.8 243.3 > > on ZFS: > > -------Sequential Output-------- ---Sequential Input-- --Random-- > -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- > Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU > 1024 22591 53.7 45602 35.1 14770 13.2 45007 83.8 94595 28.0 102.2 1.2 > > > atom# cat /boot/loader.conf > vm.kmem_size="1024M" > vm.kmem_size_max="1024M" > vfs.zfs.arc_max="96M" > > The test isn't completely fair in that the test on UFS2 is done on a > partition that resides on the first 16gb of a 2tb disk while the zfs > test is done on the enormous 1,9tb zfs pool that comes after that > partition (same disk). Can this difference in layout make up for the > huge difference in performance or is there something else in play? The > system is an Intel Atom 330 dualcore, 2gb ram, Western Digital Green > 2tb disk. Also what would be another good way to get good numbers for > comparing the performance of UFS2 vs ZFS on the same system. > > > Sincerely, > - Dan Naumov > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > >
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