[clug] Ubuntu problem with mdadm / kernel?

Steve McInerney steve at stedee.id.au
Wed Sep 5 18:28:44 MDT 2012

I've had issues in the past, not necessarily ubuntu specific, where the 
mdadm.conf becomes out of sync to reality; usually to changes I've done, but 
not updated.

sudo mdadm --examine --scan
and diff to /etc/mdadm/mdadm.conf may be worthwhile.

the 11.10 -> 12.04 beta cycle was quite nasty for me. Ended up calling it 
quits, doing a full wipe and reinstall from the 12.04 beta of the then moment. 
Some related to mdadm going lala on me, if memory serves.
Had happily upgraded thru each beta cycle since 8.10, so it was crushing to do 
a fresh & full re-install :-)

You *may* have fallen afoul of:

whereby the mdadm monitoring aborts; so you lose sight of monitoring not 
happening. Which then cascaded to what you saw?


- Steve

On 06/09/12 10:06, Edward C. Lang wrote:
> Hi,
> Is anyone aware of a recent (last three weeks?) issue with software raid
> devices on Ubuntu? I was away for a few weeks, came home on Sunday and did
> a dist-upgrade on a headless fileserver. When I rebooted it, for some
> reason one of the metadevices wasn't found - a 6TB RAID0 device on top of
> two 3TB RAID1 devices. There are five metadevices in total and the RAID0
> one was the only one which wasn't automatically detected.
> When I finally got around to determining why the server wasn't coming back
> up, I was able to manually run mdadm --assemble --scan, which found the
> missing device.  At that point I could see the LVM volume group and the
> server was able to continue booting normally.
> Perhaps the issue isn't the kernel or mdadm? Could some other package be
> causing the problem? There wasn't anything obvious on the Ubuntu
> bugtracker for mdadm or the kernel, and the #ubuntu channel on freenode
> was fairly useless.
> Regards,
> Edward.

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