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 > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mailman.mn-linux.org/pipermail/tclug-list/attachments/20120402/2871c3b7/attachment.html>