On Tue, July 26, 2011 09:55, Cindy Swearingen wrote: > > Subject: Re: [zfs-discuss] Adding mirrors to an existing zfs-pool > Date: Tue, 26 Jul 2011 08:54:38 -0600 > From: Cindy Swearingen <cindy.swearin...@oracle.com> > To: Bernd W. Hennig <consult...@hennig-consulting.com> > References: <342994905.11311662049567.JavaMail.Twebapp@sf-app1> > > Hi Bernd, > > If you are talking about attaching 4 new disks to a non redundant pool > with 4 disks, and then you want to detach the previous disks then yes, > this is possible and a good way to migrate to new disks. > > The new disks must be the equivalent size or larger than the original > disks. > > See the hypothetical example below. > > If you mean something else, then please provide your zpool status > output. > > Thanks, > > Cindy > > > # zpool status tank > pool: tank > state: ONLINE > scan: resilvered 1018K in 0h0m with 0 errors on Fri Jul 22 15:54:52 2011 > config: > > NAME STATE READ WRITE CKSUM > tank ONLINE 0 0 0 > c4t1d0 ONLINE 0 0 0 > c4t2d0 ONLINE 0 0 0 > c4t3d0 ONLINE 0 0 0 > c4t4d0 ONLINE 0 0 0 > > > # zpool attach tank c4t1d0 c6t1d0 > # zpool attach tank c4t2d0 c6t2d0 > # zpool attach tank c4t3d0 c6t3d0 > # zpool attach tank c4t4d0 c6t4d0 > > The above syntax will create 4 mirrored pairs of disks.
I was somewhat surprised when I first learned of this. In my head, I now remember it as "a single disk in ZFS seems to be treated as a one-disk mirror". Previously, in my head, single disks were very different objects from mirrors! I'm still impressed by the ability to attach and detach arbitrary numbers of disks to mirrors. It makes upgrading mirrored disks very very safe, since I can perform the entire procedure without ever reducing redundancy below my starting point (using the classic attach new, resilver, detach old sequence, repeated for however many disks were in the original mirror). -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
