-----Original message----- From: Tom H <[email protected]> Sent: Thu 23-02-2012 01:12 Subject: Re: Degraded array issues with SL 6.1 and SL 6.2 To: SL Users <[email protected]>; > On Wed, Feb 22, 2012 at 7:58 AM, Bill Maidment <[email protected]> wrote: > > -----Original message----- > > From: Bill Maidment <[email protected]> > > Sent: Mon 20-02-2012 17:43 > > Subject: Degraded array issues with SL 6.1 and SL 6.2 > > To: [email protected] <[email protected]>; > >> I have had some issues with the last two kernel releases. When a degraded > array > >> event occurs, I am unable to add a new disk back in to the array. This has > been > >> reported on Centos 6.1/6.2 and also RHEL 6.2 (see Bug 772926 - dracut > >> unable > to > >> boot from a degraded raid1 array). I have found that I need to revert to > kernel > >> 2.6.32-131.21.1.el6.x86_64 in order to be able to add the new drive. > > > > The response from RH is as follows: > > 1) If you try to re-add a disk to a running raid1 after having failed it, > > mdadm correctly rejects it as it has no way of knowing which of the disks > > are authoritative. It clearly tells you that in the error message you > > pasted into the bug. > > > > 2) You reported a Scientific Linux bug against Red Hat Enterprise Linux. > > Red Hat does not support Scientific Linux, please report bugs against > > Scientific Linux to the people behind Scientific Linux. > > > > My response is: > > 1) a) It used to work it out. b) No it does not clearly spell it out. c) > > Why > was it not a problem in earlier kernels? > > 2) Is this an SL bug? I think not! > > Bug 772926 doesn't have anything about SL. Are you referring to another bug? > > In (1) above, are they replying that you can't "--fail", "--remove", > and then "--add" the same disk or that you can't "--fail" and > "--remove" a disk, replace it, and then can't "--add" it because it's > got the same "X"/"XY" in "sdX"/"sdaXY" as the previous, failed disk? > >
Now I've had my coffee fix I have got back my sanity. I have used the following sequence of commands to remove and re-add a disk to a running RAID1 array: mdadm /dev/md3 -f /dev/sdc1 mdadm /dev/md3 -r /dev/sdc1 mdadm --zero-superblock /dev/sdc1 mdadm /dev/md3 -a /dev/sdc1 It works as expected. I just found the original error message a bit confusing when it referred to making the disk a "spare". It would seem that earlier versions of the kernel did that automatically. Cheers Bill Maidment IT Consultant to Elgas Ltd Phone: 02 4294 3649
