I was wondering if this was a good setup for a 3320 single-bus, single-host attached JBOD. There are 12 146G disks in this array: I used: zpool create pool1 \ raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 c2t6d0 c2t8d0 c2t9d0 c2t10 \ spare c2t11d0 c2t12d0 (or something very similar) This yields a 1TB file system with dual parity and two spare disks. The cu is happy, but I wonder if there are any other suggestions for making this array faster or more reliable or just "better" in your opinion. I know that "better" has different meanings under different application conditions, so I''m just looking for folks to recommend a setup and perhaps explain why they would do it that way. Thanks, Dale
On 14 May, 2007 - Dale Sears sent me these 0,9K bytes:> I was wondering if this was a good setup for a 3320 single-bus, > single-host attached JBOD. There are 12 146G disks in this array: > > I used: > > zpool create pool1 \ > raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 c2t6d0 c2t8d0 c2t9d0 > c2t10 \ > spare c2t11d0 c2t12d0 > > (or something very similar) > > This yields a 1TB file system with dual parity and two spare disks.So first any two disks can fail at the same time.. then after rebuilding, two more disks can fail.. until you''ve replaced a disk..> The cu is happy, but I wonder if there are any other suggestions for making > this array faster or more reliable or just "better" in your opinion. I > know that "better" has different meanings under different application > conditions, so I''m just looking for folks to recommend a setup and > perhaps explain why they would do it that way.That raid set will give you the same random IO performance as a single disk. Sequential IO will be better than a single disk. For instance splitting it into two raidz2 disks without spares can survive any two disks within both groups (so 2 to 4 disks can fail without data loss).. Random IO performance will be twice the single raidz2/single disk. /Tomas -- Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Ume? `- Sysadmin at {cs,acc}.umu.se
See inline near then end... Tomas ?gren wrote:> On 14 May, 2007 - Dale Sears sent me these 0,9K bytes: > >> I was wondering if this was a good setup for a 3320 single-bus, >> single-host attached JBOD. There are 12 146G disks in this array: >> >> I used: >> >> zpool create pool1 \ >> raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 c2t6d0 c2t8d0 c2t9d0 >> c2t10 \ >> spare c2t11d0 c2t12d0 >> >> (or something very similar) >> >> This yields a 1TB file system with dual parity and two spare disks. > > So first any two disks can fail at the same time.. then after > rebuilding, two more disks can fail.. until you''ve replaced a disk.. > >> The cu is happy, but I wonder if there are any other suggestions for making >> this array faster or more reliable or just "better" in your opinion. I >> know that "better" has different meanings under different application >> conditions, so I''m just looking for folks to recommend a setup and >> perhaps explain why they would do it that way. > > That raid set will give you the same random IO performance as a single > disk. Sequential IO will be better than a single disk. > > For instance splitting it into two raidz2 disks without spares can > survive any two disks within both groups (so 2 to 4 disks can fail > without data loss).. Random IO performance will be twice the single > raidz2/single disk.What would that command look like? Is this what you''re saying?: zpool create pool1 \ raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 \ raidz2 c2t6d0 c2t8d0 c2t9d0 c2t10d0 c2t11d0 c2t12d0 Thanks! Dale> /Tomas
On 18 May, 2007 - Dale Sears sent me these 1,5K bytes:> Tomas ?gren wrote: > >On 14 May, 2007 - Dale Sears sent me these 0,9K bytes: > > > >>I was wondering if this was a good setup for a 3320 single-bus, > >>single-host attached JBOD. There are 12 146G disks in this array: > >> > >>I used: > >> > >>zpool create pool1 \ > >>raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 c2t6d0 c2t8d0 c2t9d0 > >>c2t10 \ > >>spare c2t11d0 c2t12d0[..]> >That raid set will give you the same random IO performance as a single > >disk. Sequential IO will be better than a single disk. > > > >For instance splitting it into two raidz2 disks without spares can > >survive any two disks within both groups (so 2 to 4 disks can fail > >without data loss).. Random IO performance will be twice the single > >raidz2/single disk. > > What would that command look like? Is this what you''re saying?: > > zpool create pool1 \ > raidz2 c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0 \ > raidz2 c2t6d0 c2t8d0 c2t9d0 c2t10d0 c2t11d0 c2t12d0 > > Thanks!Yep. Verify performance differences in your usage case between the two methods.. Its reliability against failures is a bit more of a gamble than a big one with 2HS.. If you''re lucky, 4 disks can blow up at the same time without problems (vs 2 in your version).. If you''re unlucky, 2 disks from the same set blows up and then another one before you had the chance to replace them with cold spare(s).. If first 2 then another one during a weekend or so.. A hot spare could have saved you then.. If you have a cold spare laying around and replacing as soon as one break, this shouldn''t be a problem.. but it can make a difference, it''s up to you to decide (or attach a single additional hotspare outside the 3320). /Tomas -- Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Ume? `- Sysadmin at {cs,acc}.umu.se