[lug] how to repair GPT

[Steve A Hart]

dmesg shows repeated messages like this:
--------------------------------------------

Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
Errataon LSI53C1030 occurred.sc->req_bufflen=0x1000,xfer_cnt=0x00
sd 4:0:4:0: [sdd] Unhandled error code
sd 4:0:4:0: [sdd] Result: hostbyte=DID_SOFT_ERROR driverbyte=DRIVER_OK
sd 4:0:4:0: [sdd] CDB: Read(16): 88 00 00 00 00 03 68 71 7f f8 00 00 00 
08 00 00
end_request: I/O error, dev sdd, sector 14637170680

fsck shows:
---------------------------------------

fsck from util-linux-ng 2.17.2
e2fsck 1.41.12 (17-May-2010)
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sdd

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>


Yeah Dan, don't you miss this place?

cheers

Steve

On 04/27/2011 12:10 PM, Dan Ferris wrote:
> Hey Steve,
>
> What does dmesg show, and what does fsck complain about? If the
> filesystem is hosed you may get to redo it from scratch anyway. I don't
> think GPT matters in this case.
>
> I remember what that was 1.2 TB and we thought it was a lot lol!
>
> Dan
>
> On 4/27/2011 12:00 PM, Steve A Hart wrote:
>> Hello all,
>>
>> We had a power outage this past weekend and of course my backup server
>> went down (because I'm the idiot who has not gotten around to getting a
>> UPS for it yet). Anyway, my 7TB raid starting showing I/O errors so I
>> unmounted it.
>>
>> Disk /dev/sdd: 7494.2 GB, 7494231392256 bytes
>> 255 heads, 63 sectors/track, 911121 cylinders
>> Units = cylinders of 16065 * 512 = 8225280 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/sdd1 1 267350 2147483647+ ee GPT
>>
>> Now it refuses to mount again and fsck freaks as expected. I'm not
>> fully experienced with GPT and would appreciate any advice on how to
>> repair/recover this and get the raid mounted and functional.
>>
>> Since this is the storage area for my backup server, I technically can
>> wipe the whole thing and start from scratch but I'd like to avoid that
>> if possible.
>>
>> Thanks
>>
>> Steve
>>

-- 
Steve Hart
Systems Administrator
Colorado Center for Astrodynamics Research
University of Colorado Boulder
shart at colorado.edu
(303)492-8109