From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lutomirski Subject: Re: How to remove a device on a RAID-1 before replacing it? Date: Tue, 29 Mar 2011 17:01:39 -0400 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-btrfs To: cwillu Return-path: In-Reply-To: List-ID: On Tue, Mar 29, 2011 at 4:21 PM, cwillu wrote: > On Tue, Mar 29, 2011 at 2:09 PM, Andrew Lutomirski wro= te: >> I have a disk with a SMART failure. =A0It still works but I assume i= t'll >> fail sooner or later. >> >> I want to remove it from my btrfs volume, replace it, and add the ne= w >> one. =A0But the obvious command doesn't work: >> >> # btrfs device delete /dev/dm-5 /mnt/foo >> ERROR: error removing the device '/dev/dm-5' >> >> dmesg says: >> btrfs: unable to go below two devices on raid1 >> >> With mdadm, I would fail the device, remove it, run degraded until I >> get a new device, and hot-add that device. >> >> With btrfs, I'd like some confirmation from the fs that data is >> balanced appropriately so I won't get data loss if I just yank the >> drive. =A0And I don't even know how to tell btrfs to release the dri= ve >> so I can safely remove it. >> >> (Mounting with -o degraded doesn't help. =A0I could umount, remove t= he >> disk, then remount, but that feels like a hack.) > > There's no "nice" way to remove a failing disk in btrfs right now > ("btrfs dev delete" is more of a online management thing to politely > remove a perfectly functional disk you'd like to use for something > else.) =A0As I understand things, the only way to do it right now is = the > umount, remove disk, remount w/ degraded, and then btrfs add the new > device. > Well, the disk *is* perfectly functional. It just won't be for long. I guess what I'm saying is that either btrfs dev delete isn't really working -- I want to be able to convert to non-RAID and back or degraged and back or something else equivalent. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html