[gpfsug-discuss] File system recovery question

Jonathan Buzzard jonathan at buzzard.me.uk
Wed Feb 13 17:00:31 GMT 2013

On Wed, 2013-02-13 at 10:29 -0600, Chad Kerner wrote:
> 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.

Log a SEV1 call with IBM. If it is only one NSD that is stuffed they
might be able to get it back for you. However it is a custom procedure
that requires developer time from Poughkeepsie. It will take some time.

In the meantime I would strongly encourage you to start preparing for a
total restore, which will include recreating the file system from
scratch. Certainly if all the NSD headers are stuffed then the file
system is a total loss. However even with only one lost it is not as I
understand it certain you can get it back.

It is probably a good idea to store the NSD headers somewhere off the
file system in case some numpty wipes them. The most likely reason for
this is that they ran an distro install on a system that has direct
access to the disk.


Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.

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