[gpfsug-discuss] Lost disks

[Sven Oehme]

it can happen for multiple reasons , one is a linux install, unfortunate
there are significant more simpler explanations. Linux as well as BIOS in
servers from time to time looks for empty disks and puts a GPT label on it
if the disk doesn't have one, etc. this thread is explaining a lot of this
:

https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014439222

this is why we implemented NSD V2 format long time ago , unfortunate there
is no way to convert an V1 NSD to a V2 nsd on an existing filesytem except
you remove the NSDs one at a time and re-add them after you upgraded the
system to at least GPFS 4.1 (i would recommend a later version like 4.2.3)

some more details are here in this thread :

https://www.ibm.com/developerworks/community/forums/html/threadTopic?id=5c1ee5bc-41b8-4318-a74e-4d962f82ce2e

but a quick summary of the benefits of V2 are :

   - ‰ Support for GPT NSD ‰
   - Adds a standard disk partition table (GPT type) to NSDs ‰
      - Disk label support for Linux ‰


   - New GPFS NSD v2 format provides the following benefits: ‰
   - Includes a partition table so that the disk is recognized as a GPFS
      device ‰
      - Adjusts data alignment to support disks with a 4 KB physical block
      size ‰
      - Adds backup copies of some key GPFS data structures ‰
      - Expands some reserved areas to allow for future growth

the main reason we can't convert from V1 to V2 is the on disk format
changed significant so we would have to move on disk data which is very
risky.

hope that explains this.

Sven

On Wed, Jul 26, 2017 at 10:29 AM Mark Bush <Mark.Bush at siriuscom.com> wrote:

> I have a client has had an issue where all of the nsd disks disappeared in
> the cluster recently.  Not sure if it’s due to a back end disk issue or if
> it’s a reboot that did it.  But in their PMR they were told that all that
> data is lost now and that the disk headers didn’t appear as GPFS disk
> headers.  How on earth could something like that happen?  Could it be a
> backend disk thing?  They are confident that nobody tried to reformat disks
> but aren’t 100% sure that something at the disk array couldn’t have caused
> this.
>
>
>
> Is there an easy way to see if there is still data on these disks?
>
> Short of a full restore from backup what other options might they have?
>
>
>
> The mmlsnsd -X show’s blanks for device and device type now.
>
>
>
> # mmlsnsd -X
>
>
>
> Disk name    NSD volume ID      Device         Devtype  Node
> name                Remarks
>
>
> ---------------------------------------------------------------------------------------------------
>
> INGEST_FILEMGR_xis2301 0A23982E57FD995D   -              -
> ingest-filemgr01.a.fXXXXXXX.net (not found) server node
>
> INGEST_FILEMGR_xis2301 0A23982E57FD995D   -              -
> ingest-filemgr02.a.fXXXXXXX.net (not found) server node
>
> INGEST_FILEMGR_xis2302 0A23982E57FD9960   -              -
> ingest-filemgr01.a.fXXXXXXX.net (not found) server node
>
> INGEST_FILEMGR_xis2302 0A23982E57FD9960   -              -
> ingest-filemgr02.a.fXXXXXXX.net (not found) server node
>
> INGEST_FILEMGR_xis2303 0A23982E57FD9962   -              -
> ingest-filemgr01.a.fXXXXXXX.net (not found) server node
>
>
>
>
>
> *Mark*
>
> This message (including any attachments) is intended only for the use of
> the individual or entity to which it is addressed and may contain
> information that is non-public, proprietary, privileged, confidential, and
> exempt from disclosure under applicable law. If you are not the intended
> recipient, you are hereby notified that any use, dissemination,
> distribution, or copying of this communication is strictly prohibited. This
> message may be viewed by parties at Sirius Computer Solutions other than
> those named in the message header. This message does not contain an
> official representation of Sirius Computer Solutions. If you have received
> this communication in error, notify Sirius Computer Solutions immediately
> and (i) destroy this message if a facsimile or (ii) delete this message
> immediately if this is an electronic communication. Thank you.
> Sirius Computer Solutions <http://www.siriuscom.com>
> _______________________________________________
> gpfsug-discuss mailing list
> gpfsug-discuss at spectrumscale.org
> http://gpfsug.org/mailman/listinfo/gpfsug-discuss
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20170726/892aa5ff/attachment-0002.htm>