Hi all,
I installed Ubuntu for my parents many many moons ago. I had upgraded it as
far as Hardy and then I left it. Recently they've been complaining that
certain websites aren't working (due to flash being too old) and their
printers drivers not being fully reliable. "No problem," thinks I, I'll
just update to 11.10. I have done so, and Unity issues aside (I've
installed GNOME Classic for them now) it's gone well...
EXCEPT the computer only boots roughly 1 time in 3 (no obvious pattern).
The issue, I've found, is due to their RAID0 /home partition not
initialising correctly sometimes (sometimes it's "degraded mode", sometimes
no message at all, it just locks up). I've had a good poke around and it
seems that it doesn't work when /dev/sdb is detected as /dev/sdf instead. I
know this in itself isn't a bug, but it seems to be what is causing the
issue. I was expecting it to Just Work (TM) since it does for all the other
boxes that I have RAID on. I thought the persistent superblock should stop
this issue from happening, but autodetection seems to be failing early
during boot.
I've added relevant data to the bottom of the email to rule out some common
issues/confirm what I've done/point out an obvious issue I may have
overlooked...
For autodetection I require, according to
http://tldp.org/HOWTO/Software-RAID-HOWTO.html#toc7.2
1) Autodetection in the kernel [I have stock Ubuntu 11.10 kernel - perhaps
this is missing/missing from the initrd]
2) Persistent-superblock [mdadm claims this to be the case - see below]
3) 0xFD partition types [fdisk claims this to be the case]
From /var/log/syslog (or /var/log/messages) we get:
Dec 26 09:12:15 ann-desktop kernel: [ 3.251290] md: bind<sda5>
Dec 26 09:12:15 ann-desktop kernel: [ 3.290692] md: bind<sdb5>
Dec 26 09:12:15 ann-desktop kernel: [ 3.293935] bio: create slab <bio-1>
at 1
Dec 26 09:12:15 ann-desktop kernel: [ 3.294070] md/raid1:md0: active
with 2 out of 2 mirrors
Dec 26 09:12:15 ann-desktop kernel: [ 3.294097] md0: detected capacity
change from 0 to 151846780928
Dec 26 09:12:15 ann-desktop kernel: [ 3.296464] md0: unknown partition
table
This suggests to me that auto-detection is not occurring, so installing
something (kernel modules/settings/app/whatever) and then doing
"update-initramfs
-u" should presumably fix this issue, but I've not much longer to solve it
before I leave to go back home tomorrow. Any ideas would be greatly
appreciated.
Further details follow.
I hope you're all having a great Christmas! Happy New Year!
Cheers,
Benjie.
/ is not RAID (why bother, just replace)
/home is RAID0 (custom set up via mdadm about 4 years ago)
Two equal sized drives.
The RAID, once it's running, is absolutely fine. It's just detection that
fails.
$ sudo fdisk -l /dev/sda
Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sda1 * 63 16000739 8000338+ 83 Linux
/dev/sda2 16000740 312576704 148287982+ 5 Extended
/dev/sda5 16000803 312576704 148287951 fd Linux RAID
autodetect
$ sudo fdisk -l /dev/sdb
Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000aa89b
Device Boot Start End Blocks Id System
/dev/sdb1 63 4000184 2000061 82 Linux swap / Solaris
/dev/sdb2 16000801 312576704 148287952 5 Extended
/dev/sdb5 16000803 312576704 148287951 fd Linux RAID
autodetect
$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
[raid4] [raid10]
md0 : active raid1 sda5[0] sdb5[1]
148287872 blocks [2/2] [UU]
unused devices: <none>
$ sudo mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Fri Nov 16 12:01:45 2007
Raid Level : raid1
Array Size : 148287872 (141.42 GiB 151.85 GB)
Used Dev Size : 148287872 (141.42 GiB 151.85 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Mon Dec 26 21:06:17 2011
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : f0a0371d:12376ea7:4c4ad349:bc95e7b8
Events : 0.436
Number Major Minor RaidDevice State
0 8 5 0 active sync /dev/sda5
1 8 21 1 active sync /dev/sdb5
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