Response below... 2010/4/5 Andreas Höschler <ahoe...@smartsoft.de>
> Hi Edward, > > thanks a lot for your detailed response! > > > From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- >>> boun...@opensolaris.org] On Behalf Of Andreas Höschler >>> >>> • I would like to remove the two SSDs as log devices from the pool and >>> instead add them as a separate pool for sole use by the database to >>> see how this enhences performance. I could certainly do >>> >>> zpool detach tank c1t7d0 >>> >>> to remove one disk from the log mirror. But how can I get back the >>> second SSD? >>> >> >> If you're running solaris, sorry, you can't remove the log device. You >> better keep your log mirrored until you can plan for destroying and >> recreating the pool. Actually, in your example, you don't have a mirror >> of >> logs. You have two separate logs. This is fine for opensolaris (zpool >> >>> =19), but not solaris (presently up to zpool 15). If this is solaris, >>> and >>> >> *either* one of those SSD's fails, then you lose your pool. >> > > I run Solaris 10 (not Open Solaris)! > > You say the log mirror > > > pool: tank > state: ONLINE > scrub: none requested > config: > > NAME STATE READ WRITE CKSUM > tank ONLINE 0 0 0 > ... > > logs > c1t6d0 ONLINE 0 0 0 > c1t7d0 ONLINE 0 0 0 > > does not do me anything good (redundancy-wise)!? Shouldn't I dettach the > second drive then and try to use it for something else, may be another > machine? > > No, he did *not* say that a mirrored SLOG has no benefit, redundancy-wise. He said that YOU do *not* have a mirrored SLOG. You have 2 SLOG devices which are striped. And if this machine is running Solaris 10, then you cannot remove a log device because those updates have not made their way into Solaris 10 yet. You need pool version >= 19 to remove log devices, and S10 does not currently have patches to ZFS to get to a pool version >= 19. If your SLOG above were mirrored, you'd have "mirror" under "logs". And you probably would have "log" not "logs" - notice the "s" at the end meaning plural, meaning multiple independent log devices, not a mirrored pair of logs which would effectively look like 1 device. -- "You can choose your friends, you can choose the deals." - Equity Private "If Linux is faster, it's a Solaris bug." - Phil Harman Blog - http://whatderass.blogspot.com/ Twitter - @khyron4eva
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