At home I run an Ubuntu (6.06) file, media, web, VMWare server with 4 RAID arrays. This system has been running happily since I built it last September, but this evening while testing an Asterisk VM I noticed that the contents of the largest and most important array (md0) were no longer visible from my workstation (XP Pro). Strange, thought I, it was fine this afternoon.
I can see no problems with Samba as my other shares are working fine, so I SSH to the server and ls -la the array's mount point (/srv/videos), which returns[Random expletive], thought I, my files are gone, however a quick df -H confirms the array still has data
So I check the array
Filesystem Size Used Avail Use% Mounted on
/dev/md0 946G 745G 153G 83% /srv/videos
No problems there (Except the failed disk in md3 I already knew, and didn't care, about).
Personalities : [raid1] [raid5]
md3 : active raid1 hda3
27993152 blocks [2/1] [U_]
md2 : active raid1 hda1 hdb1
48064 blocks [2/2] [UU]
md1 : active raid1 hde1 sde1
195357632 blocks [2/2] [UU]
md0 : active raid5 sda1 sdd1 sdc1 sdb1
937705728 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
unused devices: <none>
>mdadm --query /dev/md0
/dev/md0: 894.27GiB raid5 4 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md0: No md super block found, not an md component.
I'm now more than a little concerned so I check the disks
>mdadm --detail /dev/md0
Version : 00.90.03
Creation Time : Sat Sep 23 22:20:25 2006
Raid Level : raid5
Array Size : 937705728 (894.27 GiB 960.21 GB)
Device Size : 312568576 (298.09 GiB 320.07 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Mon Mar 5 17:30:37 2007
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : 93fe44fd:f2cffc76:5ddc9418:d343a912
Events : 0.6029041
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 8 33 2 active sync /dev/sdc1
3 8 49 3 active sync /dev/sdd1
I now think I've found the problem, but daren't try anything lest I make things worse. Can anyone help me get my RAID back in working order without losing the video collection I've spent the last 3 years putting together?
>mdadm --query /dev/sda1
/dev/sda1: is not an md array
/dev/sda1: device 0 in 4 device active raid5 md0. Use mdadm --examine for more detail.
>mdadm --query /dev/sdb1
/dev/sdb1: is not an md array
/dev/sdb1: device 1 in 4 device active raid5 md0. Use mdadm --examine for more detail.
>mdadm --query /dev/sdc1
/dev/sdc1: is not an md array
/dev/sdc1: device 2 in 4 device active raid5 md0. Use mdadm --examine for more detail.
>mdadm --query /dev/sdd1
/dev/sdd1: is not an md array
/dev/sdd1: No md super block found, not an md component.
>mdadm --examine /dev/sdd1
mdadm: No super block found on /dev/sdd1 (Expected magic a92b4efc, got 00000000)
And before anyone asks, no, I have not tried turning it off and on again, as it's also my web server and I'd like to keep it running if possible, however I will do if rebooting is likely to help.