-----Original message-----
From:	Bill Maidment <[log in to unmask]>
Sent:	Mon 20-02-2012 17:43
Subject:	Degraded array issues with SL 6.1 and SL 6.2
To:	[log in to unmask] <[log in to unmask]>; 
> Hi, just a heads up.
> 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.
> 
> Cheers
> Bill Maidment
> IT Consultant to Elgas Ltd
> Phone: 02 4294 3649

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!

Cheers
Bill Maidment
IT Consultant to Elgas Ltd
Phone: 02 4294 3649