On Mar 8, 2010, at 5:57 PM, Matt Cowger wrote: > Hi Everyone, > > It looks like I’ve got something weird going with zfs performance on a > ramdisk….ZFS is performing not even a 3rd of what UFS is doing. > > Short version: > > Create 80+ GB ramdisk (ramdiskadm), system has 96GB, so we aren’t swapping > Create zpool on it (zpool create ram….) > Change zfs options to turn off checksumming (don’t want it or need it), > atime, compression, 4K block size (this is the applications native blocksize) > etc. > Run a simple iozone benchmark (seq. write, seq. read, rndm write, rndm read). > > Same deal for UFS, replacing the ZFS stuff with newfs stuff and mounting the > UFS forcedirectio (no point in using a buffer cache memory for something > that’s already in memory)
Did you also set primarycache=none? -- richard > > Measure IOPs performance using iozone: > > iozone -e -i 0 -i 1 -i 2 -n 5120 -O -q 4k -r 4k -s 5g > > With the ZFS filesystem I get around: > ZFS > (seq write) 42360 (seq read)31010 (random > read)20953 (random write)32525 > Not SOO bad, but here’s UFS: > UFS > (seq write )42853 (seq read) 100761 (random read) > 100471 (random write) 101141 > > For all tests besides the seq write, UFS utterly destroys ZFS. > > I’m curious if anyone has any clever ideas on why this huge disparity in > performance exists. At the end of the day, my application will run on either > filesystem, it just surprises me how much worse ZFS performs in this > (admittedly edge case) scenario. > > --M > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance http://nexenta-atlanta.eventbrite.com (March 16-18, 2010) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
