I've been having the same problem. I'm attaching my mdadm bug script output (with a few sensitive bits redacted). Also:
| $ sudo mdadm -Ds | ARRAY /dev/md/0 metadata=0.90 UUID=222a461f:8303a4d2:4a90023e:7c4f4b06 -Julian
--- mount output
/dev/mapper/vg0-main_crypt on / type xfs (rw,noatime)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
/dev/mapper/vg0-boot on /boot type xfs (rw,noatime)
/dev/mapper/vg0-bare on /media/bare type xfs (rw,noatime)
/dev/mapper/usbdisk0_crypt on /media/usbdisk0 type fuseblk
(rw,noexec,nosuid,nodev,allow_other,default_permissions,blksize=4096)
/dev/sdd1 on /media/usbdisk1 type fuseblk
(rw,noexec,nosuid,nodev,allow_other,default_permissions,blksize=4096)
(bind mounts redacted for privacy reasons)
--- mdadm.conf
# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#
# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
DEVICE partitions
# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes
# automatically tag new arrays as belonging to the local system
HOMEHOST <system>
# instruct the monitoring daemon where to send mail alerts
MAILADDR root
# definitions of existing MD arrays
#ARRAY /dev/md0 level=raid1 num-devices=2
UUID=222a461f:8303a4d2:53851496:d0cc6843
#ARRAY /dev/md/0 level=raid1 num-devices=2
UUID=222a461f:8303a4d2:53851496:d0cc6843
#ARRAY /dev/md0 level=raid1 num-devices=2
UUID=222a461f:8303a4d2:4a90023e:7c4f4b06
ARRAY /dev/md/0 level=raid1 num-devices=2
UUID=222a461f:8303a4d2:4a90023e:7c4f4b06
# This file was auto-generated on Thu, 25 Dec 2008 23:23:49 +0000
# by mkconf $Id$
--- /proc/mdstat:
Personalities : [raid1]
md0 : active raid1 sda1[0] sdb1[1]
488383936 blocks [2/2] [UU]
bitmap: 6/233 pages [24KB], 1024KB chunk
unused devices: <none>
--- /proc/partitions:
major minor #blocks name
8 0 488386584 sda
8 1 488384001 sda1
8 16 488386584 sdb
8 17 488384001 sdb1
9 0 488383936 md0
253 0 122880 dm-0
253 1 456257536 dm-1
253 2 32002048 dm-2
8 32 488386584 sdc
8 33 32098 sdc1
8 34 488351902 sdc2
8 48 488386584 sdd
8 49 488384001 sdd1
253 3 456256508 dm-3
253 4 488351386 dm-4
--- initrd.img-2.6.30-2-amd64:
50770 blocks
66818791d08ce4ca57f4989c6e3b7d54 ./etc/mdadm/mdadm.conf
13b4102c11a94b2d9e300b617c9f806a
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-mod.ko
988339597939b708e346a61bd4a6a343
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-crypt.ko
f4762b1f0d4f3e303072c637753ce366
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-snapshot.ko
16ee20acf5405ba0947bdb6cc9cd54b9
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-log.ko
4863981fb1954174ea77b9f476991536
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-region-hash.ko
165fe6c1793eaedea1aa2db2cdb1aed3
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/dm-mirror.ko
fac315a287715e2ca70756f758912cb0
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/md-mod.ko
3a081ea94071a3e5b2e72dd4c67eb671
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/linear.ko
20d388cd4ea7636d903ab522c20a97bb
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/multipath.ko
60c056c6dbbd2c46e932f5b25be86354
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/raid0.ko
2fc7df8b12010f788514021ddab80f12
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/raid1.ko
3c33b6068a91402431f25ab2a855fe08
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/raid6_pq.ko
b1538856e0c3b7883940eeb800f68e20
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/raid456.ko
773eeeefa6a5cdd4930ae7be012e37a6
./lib/modules/2.6.30-2-amd64/kernel/drivers/md/raid10.ko
7966ccb72128e7a86d09b7c3b5df7557 ./sbin/mdadm
6b782ae76f866914ec236b2d14b43f24 ./scripts/local-top/mdadm
--- /proc/modules:
dm_crypt 12920 2 - Live 0xffffffffa01ba000
dm_mirror 14616 0 - Live 0xffffffffa01b1000
dm_region_hash 12704 1 dm_mirror, Live 0xffffffffa01ab000
dm_log 9924 2 dm_mirror,dm_region_hash, Live 0xffffffffa01a3000
dm_snapshot 22860 0 - Live 0xffffffffa0198000
dm_mod 59256 17 dm_crypt,dm_mirror,dm_log,dm_snapshot, Live 0xffffffffa0184000
raid1 21104 1 - Live 0xffffffffa0179000
md_mod 86628 2 raid1, Live 0xffffffffa015e000
--- /var/log/syslog:
--- volume detail:
/dev/sda is not recognised by mdadm.
/dev/sda1:
Magic : a92b4efc
Version : 0.90.00
UUID : 222a461f:8303a4d2:4a90023e:7c4f4b06
Creation Time : Tue Dec 30 02:18:29 2008
Raid Level : raid1
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Array Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Update Time : Thu Jan 28 03:52:00 2010
State : active
Internal Bitmap : present
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : c70fe3cb - correct
Events : 42593
Number Major Minor RaidDevice State
this 0 8 1 0 active sync /dev/sda1
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
--
/dev/sdb is not recognised by mdadm.
/dev/sdb1:
Magic : a92b4efc
Version : 0.90.00
UUID : 222a461f:8303a4d2:4a90023e:7c4f4b06
Creation Time : Tue Dec 30 02:18:29 2008
Raid Level : raid1
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Array Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Update Time : Thu Jan 28 03:52:00 2010
State : active
Internal Bitmap : present
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : c70fe3dd - correct
Events : 42593
Number Major Minor RaidDevice State
this 1 8 17 1 active sync /dev/sdb1
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
--
/dev/sdc is not recognised by mdadm.
/dev/sdc1 is not recognised by mdadm.
/dev/sdc2 is not recognised by mdadm.
/dev/sdd is not recognised by mdadm.
/dev/sdd1 is not recognised by mdadm.
--- /proc/cmdline
BOOT_IMAGE=/vmlinuz-2.6.30-2-amd64 root=/dev/mapper/vg0-main_crypt ro single
gfxpayload=text
--- grub2:
insmod raid
insmod raid
set root=(vg0-boot)
linux /vmlinuz-2.6.30-2-amd64 root=/dev/mapper/vg0-main_crypt ro
gfxpayload=text quiet
insmod raid
set root=(vg0-boot)
linux /vmlinuz-2.6.30-2-amd64 root=/dev/mapper/vg0-main_crypt ro
single gfxpayload=text
--- grub legacy:
kernel /vmlinuz-2.6.26-1-amd64 root=/dev/mapper/sda2_crypt ro vga=ext
quiet
kernel /vmlinuz-2.6.26-1-amd64 root=/dev/mapper/sda2_crypt ro vga=ext
quiet single
--- udev:
ii udev 149-1 /dev/ and hotplug management daemon
4a574fcd059040d33ea18a8aa605a184 /lib/udev/rules.d/64-md-raid.rules
--- /dev:
brw-rw---- 1 root disk 9, 0 2009-12-27 11:23 /dev/md0
/dev/disk/by-id:
total 0
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 ata-ST3500320AS_XXXXXXXX -> ../../sdb
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 ata-ST3500320AS_XXXXXXXX-part1 ->
../../sdb1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 ata-ST3500418AS_XXXXXXXX -> ../../sda
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 ata-ST3500418AS_XXXXXXXX-part1 ->
../../sda1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-temporary-cryptsetup-1591 ->
../../dm-4
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-usbdisk0_crypt -> ../../dm-4
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-vg0-bare -> ../../dm-2
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-vg0-boot -> ../../dm-0
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-vg0-main -> ../../dm-1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 dm-name-vg0-main_crypt -> ../../dm-3
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
dm-uuid-LVM-I5neqRZUWY155z7VQibOefNIxeF5IjSZcAGpFDukI3dceg3ut9hKi4xUAgI42gUP ->
../../dm-1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
dm-uuid-LVM-I5neqRZUWY155z7VQibOefNIxeF5IjSZdOSBnNRbiOlzqTmy4omj5h9wffcT80Mz ->
../../dm-0
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
dm-uuid-LVM-I5neqRZUWY155z7VQibOefNIxeF5IjSZWDSh2Ak82Lw2IVMP3skRlDfzBF1sKGGr ->
../../dm-2
lrwxrwxrwx 1 root root 9 2009-12-27 11:23
md-uuid-222a461f:8303a4d2:4a90023e:7c4f4b06 -> ../../md0
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 scsi-SATA_ST3500320AS_XXXXXXXX ->
../../sdb
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 scsi-SATA_ST3500320AS_XXXXXXXX-part1
-> ../../sdb1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 scsi-SATA_ST3500418AS_XXXXXXXX ->
../../sda
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 scsi-SATA_ST3500418AS_XXXXXXXX-part1
-> ../../sda1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23
usb-Seagate_FreeAgent_Go_XXXXXXXX-0:0 -> ../../sdc
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
usb-Seagate_FreeAgent_Go_XXXXXXXX-0:0-part1 -> ../../sdc1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
usb-Seagate_FreeAgent_Go_XXXXXXXX-0:0-part2 -> ../../sdc2
lrwxrwxrwx 1 root root 9 2009-12-27 11:23
usb-Seagate_FreeAgent_Go_XXXXXXXX-0:0 -> ../../sdd
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
usb-Seagate_FreeAgent_Go_XXXXXXXX-0:0-part1 -> ../../sdd1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 wwn-0x5000c5000e26fe83 -> ../../sdb
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 wwn-0x5000c5000e26fe83-part1 ->
../../sdb1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 wwn-0x5000c500163193c7 -> ../../sda
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 wwn-0x5000c500163193c7-part1 ->
../../sda1
/dev/disk/by-label:
total 0
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 jume-usbdisk0-util -> ../../sdc1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 jume-usbdisk1 -> ../../sdd1
/dev/disk/by-path:
total 0
lrwxrwxrwx 1 root root 9 2009-12-27 11:23
pci-0000:00:1d.7-usb-0:2:1.0-scsi-0:0:0:0 -> ../../sdc
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
pci-0000:00:1d.7-usb-0:2:1.0-scsi-0:0:0:0-part1 -> ../../sdc1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
pci-0000:00:1d.7-usb-0:2:1.0-scsi-0:0:0:0-part2 -> ../../sdc2
lrwxrwxrwx 1 root root 9 2009-12-27 11:23
pci-0000:00:1d.7-usb-0:3:1.0-scsi-0:0:0:0 -> ../../sdd
lrwxrwxrwx 1 root root 10 2009-12-27 11:23
pci-0000:00:1d.7-usb-0:3:1.0-scsi-0:0:0:0-part1 -> ../../sdd1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 pci-0000:00:1f.2-scsi-0:0:0:0 ->
../../sda
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 pci-0000:00:1f.2-scsi-0:0:0:0-part1
-> ../../sda1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 pci-0000:00:1f.2-scsi-0:0:1:0 ->
../../sdb
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 pci-0000:00:1f.2-scsi-0:0:1:0-part1
-> ../../sdb1
lrwxrwxrwx 1 root root 9 2009-12-27 11:23 pci-0000:02:00.0-scsi-0:0:0:0 ->
../../sr0
/dev/disk/by-uuid:
total 0
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 67EB38E2567CFE7F -> ../../sdc1
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 c4843a6d-c352-4d1f-990f-e4d1509b85f0
-> ../../sdc2
lrwxrwxrwx 1 root root 10 2009-12-27 11:23 CE442EAF442E99EB -> ../../sdd1
/dev/md:
total 0
lrwxrwxrwx 1 root root 6 2009-12-27 11:23 0 -> ../md0
Auto-generated on Thu, 28 Jan 2010 03:52:01 +0000
by mdadm bugscript 3.0.3-2
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