I have an old (well, fairly old) WD NAS which has two 1Tb disk drives
configured to be one big disk drive using RAID. It's been sat on the
shelf for two or three years at least so I was actually quite
pleasantly surprised when it booted.
However the RAID is broken, the second disk drive doesn't get added to
the RAID array. The NAS's configuration GUI says that both physical
disk drives are healthy/ok but marks the second half of the single
RAID virtual disk as 'failed'.
I have ssh access to the NAS (and root) and I'm quite at home on the
Unix/Linux command line and doing sysadmin type things but I'm a total
newbie as regards RAID.
So how can I set about diagnosing and fixing this? I can't even find
anything that tells me how the RAID is configured at the moment. At
the most basic level 'mount' shows:-
~ # mount
/dev/root on / type ext3 (rw,noatime,data=ordered)
proc on /proc type proc (rw)
sys on /sys type sysfs (rw)
/dev/pts on /dev/pts type devpts (rw)
securityfs on /sys/kernel/security type securityfs (rw)
/dev/md3 on /var type ext3 (rw,noatime,data=ordered)
/dev/md2 on /DataVolume type xfs (rw,noatime,uqnoenforce)
/dev/ram0 on /mnt/ram type tmpfs (rw)
/dev/md2 on /shares/Public type xfs (rw,noatime,uqnoenforce)
/dev/md2 on /shares/Download type xfs (rw,noatime,uqnoenforce)
/dev/md2 on /shares/chris type xfs (rw,noatime,uqnoenforce)
/dev/md2 on /shares/laptop type xfs (rw,noatime,uqnoenforce)
/dev/md2 on /shares/dps type xfs (rw,noatime,uqnoenforce)
/dev/md2 on /shares/ben type xfs (rw,noatime,uqnoenforce)
~ #
... and fdisk:-
~ # fdisk -l
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 5 248 1959930 fd Linux raid autodetect
/dev/sda2 249 280 257040 fd Linux raid autodetect
/dev/sda3 281 403 987997+ fd Linux raid autodetect
/dev/sda4 404 121601 973522935 fd Linux raid autodetect
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 5 248 1959930 fd Linux raid autodetect
/dev/sdb2 249 280 257040 fd Linux raid autodetect
/dev/sdb3 281 403 987997+ fd Linux raid autodetect
/dev/sdb4 404 121601 973522935 fd Linux raid autodetect
There should be a /dev/md4. :-
/proc # more mdstat
Personalities : [linear] [raid0] [raid1]
md2 : active raid1 sda4[0]
973522816 blocks [2/1] [U_]
md1 : active raid1 sdb2[1] sda2[0]
256960 blocks [2/2] [UU]
md3 : active raid1 sdb3[1] sda3[0]
987904 blocks [2/2] [UU]
md4 : active raid1 sdb4[0]
973522816 blocks [2/1] [U_]
md0 : active raid1 sdb1[1] sda1[0]
1959808 blocks [2/2] [UU]
unused devices: <none>
Oh, and the kernel is:-
Linux WDbackup 2.6.24.4 #1 Thu Apr 1 16:43:58 CST 2010 armv5tejl unknown
--
Chris Green
