Re: Mdadm device reassignment

[Garrett Reid <garrett.reid@gmail.com>]

On Feb 17, 2011, at 6:43 PM, Tom H wrote:

> On Thu, Feb 17, 2011 at 6:40 PM, Garrett Reid <garrett.reid@gmail.com> wrote:
>> 
>> Hi all, I just installed the new stable Squeeze system, and moved over a
>> raid5 from an older system. For some reason, it now wants to mount as md127
>> instead of md0. I've been unable to map it back to md0.
>>> 
>>> root@jupiter:~# mdadm --stop /dev/md127
>>> mdadm: stopped /dev/md127
>>> root@jupiter:~# mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1
>>> /dev/sde1
>>> mdadm: /dev/md0 has been started with 4 drives.
>>> root@jupiter:~# cat /proc/mdstat
>>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
>>> [raid4] [raid10]
>>> md0 : active (auto-read-only) raid5 sde1[0] sdb1[3] sdd1[2] sdc1[1]
>>>       4395407808 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>> 
>> This works fine, until reboot, at which point we're back to md127. In
>> /var/log/syslog, I find this little oddity:
>>> 
>>> Feb 17 15:33:35 jupiter mdadm[1580]: DeviceDisappeared event detected on
>>> md device /dev/md0
>>> Feb 17 15:33:35 jupiter mdadm[1580]: NewArray event detected on md device
>>> /dev/md127
> 
> Does stopping and re-assembling the array with "--update=homehost"
> make it come back up as md0 after a reboot?

That did the trick, thanks! :)

I don't think I was entirely clear with my initial email; this was a different machine than the last one, not just a squeeze update (so it was a moving-raid5-issue, not a squeeze-update-issue)