[gpfsug-discuss] File system recovery question

[Chad Kerner]

I have a file system, and it appears that someone dd'd over the first part of one of the NSD's with zero's.  I see the device in multipath. I can fdisk and dd the device out.

Executing od shows it is zero's.
(! 21)-> od /dev/mapper/dh1_vd05_005 | head -n 5
0000000 000000 000000 000000 000000 000000 000000 000000 000000
*
0040000 120070 156006 120070 156006 120070 156006 120070 156006

Dumping the header of one of the other disks shows read data for the other NSD's in that file system.

(! 25)-> mmlsnsd -m | grep dh1_vd05_005 
 Disk name    NSD volume ID      Device         Node name                Remarks
---------------------------------------------------------------------------------------
 dh1_vd05_005 8D8EEA98506C69CE   -              myhost (not found) server node

(! 27)-> mmnsddiscover -d dh1_vd05_005
mmnsddiscover:  Attempting to rediscover the disks.  This may take a while ...
myhost:  Rediscovery failed for dh1_vd05_005.
mmnsddiscover:  Finished.


Wed Feb 13 09:14:03.694 2013: Command: mount desarchive
Wed Feb 13 09:14:07.101 2013: Disk failure.  Volume desarchive. rc = 19. Physical volume dh1_vd05_005.
Wed Feb 13 09:14:07.102 2013: File System desarchive unmounted by the system with return code 5 reason code 0
Wed Feb 13 09:14:07.103 2013: Input/output error
Wed Feb 13 09:14:07.102 2013: Failed to open desarchive.
Wed Feb 13 09:14:07.103 2013: Input/output error
Wed Feb 13 09:14:07.102 2013: Command: err 666: mount desarchive
Wed Feb 13 09:14:07.104 2013: Input/output error
Wed Feb 13 09:14:07 CST 2013: mmcommon preunmount invoked.  File system: desarchive  Reason: SGPanic

Is there any way to repair the header on the NSD?

Thanks for any ideas!
Chad