If you do have to replace the drive - you will need to add the new drive, then partition the new drive to match the old drive partition size layout, make them as type "fd" and then do the -add command for each partition you are re-adding into your mirror sets using mdadm. Good luck! On 04/02/2012 11:44 AM, Wayne Johnson wrote: > It's been a while since I did this. A search on google gives > http://www.tcpdump.com/kb/os/linux/removing-failed-raid-devices.html > which seems right. > > The commands (you will have to adjust it for your configuration) would be: > > mdadm /dev/md0 --fail /dev/sdc1 > This will fail the suspect drive (if not already). > > mdadm /dev/md0 --remove /dev/sdc1 > This will remove the drive from the array. > > mdadm /dev/md0 --add /dev/sdc1 > This adds the drive back into the array. It will then resync the failed > drive. You can see this by doing cat /proc/mdstat: > > # cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] > md0 : active raid5 sdc1[1] sdb1[0] sdd1[2] > 8385664 blocks level 5, 64k chunk, algorithm 2 [3/2] [U_U] > [=========>...........] recovery = 47.8% (2007428/4192832) finish=0.5min > speed=62732K/sec > > unused devices: > > > > --- > Wayne Johnson, | There are two kinds of people: Those > 3943 Penn Ave. N. | who say to God, "Thy will be done," > Minneapolis, MN 55412-1908 | and those to whom God says, "All right, > (612) 522-7003 | then, have it your way." --C.S. Lewis > > ------------------------------------------------------------------------ > *From:* Mike Miller <mbmiller+l at gmail.com> > *To:* Wayne Johnson <wdtj at yahoo.com>; TCLUG Mailing List > <tclug-list at mn-linux.org> > *Sent:* Monday, April 2, 2012 10:38 AM > *Subject:* Re: [tclug-list] fixing a RAID1 after drive failure > > On Mon, 2 Apr 2012, Wayne Johnson wrote: > > > On Mon, 2 Apr 2012, Mike Miller wrote: > > > >> Suppose one drive failed in my RAID1 mirrored pair. Can I then > simply pull the bad drive, replace it with a good one (brand new), > and have it work? Will it just automagically rebuild the RAID1 by > mirroring onto the new drive? > >> > >> This is Ubuntu software RAID1. > > > > Actually, in my experience, the drive may not have a permement > failue. You can re-activate the drive again, it will resync the > failed drive, and you are running again. If it happens too > frequently, replace the drive. > > How do I reactivate a drive? That sounds like a great idea. > > Mike > > > > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list