Cant read superblocks
I have a Dell PowerEdge R910 with a PERC 700 controller that has a virtual drive
configured as a RAID 5 with 15 disks in it. We're running CentOS 5.10 at the moment,
and I created a 15Tb ext3 filesystem on that RAID group (set this up a few years back)
that has been running fine up until yesterday. I had the opportunity to add another PERC
H810 controller along with a PowerVault MD1200 to add more space (44Tb as XFS), but when
we went to turn the server back on, we noticed one of the disks in the RAID group had
apparently failed. I didn't think much of it at the time, as it was a RAID 5, but when
the server came up and I tried to mount it, I received the following error:
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
missing codepage or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
I tried to get a listing of backup superblocks by doing the following:
[root@raos_apps01 ~]# mke2fs -b 8192 -n /dev/sdb1
Warning: blocksize 8192 not usable on most systems.
mke2fs 1.39 (29-May-2006)
mke2fs: 8192-byte blocks too big for system (max 4096)
Proceed anyway? (y,n) y
Warning: 8192-byte blocks too big for system (max 4096), forced to continue
Filesystem label=
OS type: Linux
Block size=8192 (log=3)
Fragment size=8192 (log=3)
1828894848 inodes, 1830420355 blocks
91521017 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4311218176
27934 block groups
65528 blocks per group, 65528 fragments per group
65472 inodes per group
Superblock backups stored on blocks:
65528, 196584, 327640, 458696, 589752, 1638200, 1769256, 3210872,
5307768, 8191000, 15923304, 22476104, 40955000, 47769912, 143309736,
157332728, 204775000, 429929208, 1023875000, 1101329096, 1289787624
But I am unable to actually use any of these, as they all end up giving the same error:
[root@raos_apps01 ~]# e2fsck -b 65528 /dev/sdb1
e2fsck 1.39 (29-May-2006)
e2fsck: Bad magic number in super-block while trying to open /dev/sdb1
The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
any idea how I can get the FS back? I ordered another drive to replace the failed on
thinking that *might* be part of the problem, so I will have to wait and see on that, but
I SHOULD be able to mount it, but I am not able to.
Thanks in advance
Michael
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