On Tue, Jul 5, 2011 at 6:54 AM, Lanky Doodle <lanky_doo...@hotmail.com> wrote: > OK, I have finally settled on hardware; > > 2x LSI SAS3081E-R controllers > 2x Seagate Momentus 5400.6 rpool disks > 15x Hitachi 5K3000 'data' disks > > I am still undecided as to how to group the disks. I have read elsewhere that > raid-z1 is best suited with either 3 or 5 disks and raid-z2 is better suited > with 6 or 10 disks - is there any truth in this, although I think this was in > reference to 4K sector disks; > > 3x 5 drive z1 = 24t usable > 2x 6 drive z2 = 16t usable
Take a look at https://spreadsheets.google.com/spreadsheet/ccc?key=0AtReWsGW-SB1dFB1cmw0QWNNd0RkR1ZnN0JEb2RsLXc&hl=en_US I did a bunch of testing with 40 drives. I varied the configuration between extremes of 10 vdevs of 4 disks each to one vdev of all 40 drives. All vdevs were raidz2, so my net capacity changed, but I was looking for _relative_ performance differences. I did not test sequential reads, as that was not one of our expected I/O patterns. I believe the OS was Solaris 10U8. I know it was at least zpool version 15 and may have been 22. I used the same 40 drives in all the test cases as I had seen differences between drives, and choose 40 that all had roughly matching svc_t values (from iostat). Eventually we had Sun/Oracle come in and replace any drive who's svc_t was substantially higher than the others (these drives also usually had lots of added bad blocks mapped). > keeping to those recommendations or > > 2x 7 disk z2 = 20t usable with 1 cold/warm/hot spare The testing was utilizing a portion of our drives, we have 120 x 750 SATA drives in J4400s dual pathed. We ended up with 22 vdevs each a raidz2 of 5 drives, with one drive in each of the J4400, so we can lose two complete J4400 chassis and not lose any data. -- {--------1---------2---------3---------4---------5---------6---------7---------} Paul Kraus -> Senior Systems Architect, Garnet River ( http://www.garnetriver.com/ ) -> Sound Coordinator, Schenectady Light Opera Company ( http://www.sloctheater.org/ ) -> Technical Advisor, RPI Players _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
