View Full Version : [ubuntu_studio] 13.04: degraded RAID at boot

April 28th, 2013, 06:25 PM
I have my /home on a three-disk software RAID 5, with a separate HDD for the OS. Previously I was using 32-bit Ubuntu Studio 12.10 and had no problems with the RAID.

Yesterday I installed 64-bit UbuStu (on a separate partition). (As the installer doesn't seem to cope with RAIDs, I always install without specifying /home, boot the fresh install and add a line in fstab for md0.) Since then, in about three out of five boots, I've had a warning of a degraded RAID and the usual "do you wish to start with a degraded RAID y/n?".

Once I'm logged in, every time I've had the warning I've checked with...

sudo mdadm -D /dev/md0
...and the output is always:

Version : 1.2
Creation Time : Sun Jun 3 18:17:31 2012
Raid Level : raid5
Array Size : 976763904 (931.51 GiB 1000.21 GB)
Used Dev Size : 488381952 (465.76 GiB 500.10 GB)
Raid Devices : 3
Total Devices : 3
Persistence : Superblock is persistent

Update Time : Sun Apr 28 18:08:13 2013
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 512K

Name : pompeii:0 (local to host pompeii)
UUID : bc308088:a37f3e78:e10000d6:079676d7
Events : 205

Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1

From a bit of searching and reading, I think "clean" and having all three active and working suggests I've nothing to worry about, is that so? If there is nothing wrong with my RAID, why am I getting the warning when booting up and what can I do to rectify it?

April 28th, 2013, 06:53 PM
It looks fine. But if your /home is on a RAID I would try specifying it when installing. I don't know how UbuStu installs, if it's similar to the live cd and the only problem is not having the mdadm package included, you can boot in live mode, add the package, assemble the mdadm devices if needed and then start the installation from the icon on the desktop (not rebooting the machine).
The installer should see the activated mdadm arrays then.

If you installed without /home specified, it would create a home folder in /. Did you delete this folder before attaching md0 as /home? If you didn't they might clash, but I'm not sure about that. That is one of the reasons why I would try attaching /home during the install, so there is no confusion with creating a home folder in /.

April 28th, 2013, 07:56 PM
Many thanks, that's re-assuring about the RAID.

Years ago, UbuStu used to have the old alt-install style installer so the RAID wasn't a problem. I think now it uses the same live CD as regular Ubuntu: I'll try installing that way the next time I need to (I don't fancy re-installing it now just to try it out ;-) ).

Oops, no, I didn't delete the /home before attaching md0. However, looking in /, there's a folder called /home, which contains a folder with my username and opening that shows my Home (the highlight in the Nautilus sidebar is on Home in places) -- is that as it should be, or totally messed up? :lol:

April 28th, 2013, 08:01 PM
Now that md0 is mounted as /home, it's opening the raid as /home. Not sure if it would work if you temporarily comment out the md0 entry in fstab. It might not let you login with commented out /home. Then reboot and see if there is home folder existing on root.

Or boot in live mode and check the / partition and whether it has a home folder with data in it.

April 28th, 2013, 08:41 PM
I've booted from the live CD and and in /home/USERNAME there's a load of empty folders (not what I seen when md0 is mounted), the usual user stuff: Desktop, Documents, Downloads, Music, Pictures etc.

There's also a number of hidden folders: .cache, .config, .dbus, .gconf, .gvfs, .local. And a load of config files, too: .bash_history, .bash_logout, .bashrc, .dmrc, .ICEauthority, .profile, .Xauthority, .Xauthority.AB05VW, .Xdefaults, .xscreensaver and .xsession-errors.

So is it safe to delete all of those? I'll have to do so as root for some of them, but that won't be a problem.

April 28th, 2013, 09:05 PM
It looks safe since you are mounting md0 as /home and none of those folders should be used anyway. Just for any case, you might actually move them on external disk or to another folder in /, in case you need to put something back later.

Yeah, because it's your Home folder (the new installation I mean), it will need root permissions to move them.

April 28th, 2013, 11:24 PM
I moved all the contents of /home to another folder.

On reboot, there was a degraded RAID warning and shortly after entering y it spontaneously rebooted. It came up with a degraded RAID warning again and then just seemed to hang a short while after entering y. On the third attempt, it booted normally and the RAID is showing clean, three active devices, three working devices and all three active sync. Bizarre.

I did manage to note the error messages from the RAID, which I've seen on previous occasions:

mdadm: CREATE user root not found
mdadm: CREATE group disk not found

I've not been able to find anything pertinent about those messages.