[gpfsug-discuss] Server lost NSD mappings

[Sven Oehme]

Jared,

if time permits i would open a PMR to check what happened. as i stated in 
my first email it could be multiple things, the GPT restore is only one 
possible of many explanations and some more simple reasons could explain 
what you see as well. get somebody from support check the state and then 
we know for sure. it would give you also peace of mind that it doesn't 
happen again when you are in production.
if you feel its not worth and you don't wipe any important information 
start over again.

btw. the newer BIOS versions of IBM servers have a option from preventing 
the GPT issue from happening : 

[root at gss02n1 ~]# asu64 showvalues DiskGPTRecovery.DiskGPTRecovery
IBM Advanced Settings Utility version 9.61.85B
Licensed Materials - Property of IBM
(C) Copyright IBM Corp. 2007-2014 All Rights Reserved
IMM LAN-over-USB device 0 enabled successfully.
Successfully discovered the IMM via SLP.
Discovered IMM at IP address 169.254.95.118
Connected to IMM at IP address 169.254.95.118
DiskGPTRecovery.DiskGPTRecovery=None=<Automatic>

if you set it the GPT will never get restored. you would have to set this 
on all the nodes that have access to the disks.

------------------------------------------
Sven Oehme 
Scalable Storage Research 
email: oehmes at us.ibm.com 
Phone: +1 (408) 824-8904 
IBM Almaden Research Lab 
------------------------------------------



From:   Jared David Baker <Jared.Baker at uwyo.edu>
To:     gpfsug main discussion list <gpfsug-discuss at gpfsug.org>
Date:   10/29/2014 10:30 AM
Subject:        Re: [gpfsug-discuss] Server lost NSD mappings
Sent by:        gpfsug-discuss-bounces at gpfsug.org



Thanks for all the information. I?m not exactly sure what happened during 
the firmware update of the HCAs (another admin). But I do have all the 
stanza files that I used to create the NSDs. Possible to utilize them to 
just regenerate the NSDs or is it consensus that the FS is gone? As the 
system was not in production (yet) I?ve got no problem delaying the 
release and running some tests to verify possible fixes. The system was 
already unmounted, so it is a completely inactive FS across the cluster.
 
Thanks,
 
Jared
 
From: gpfsug-discuss-bounces at gpfsug.org [
mailto:gpfsug-discuss-bounces at gpfsug.org] On Behalf Of Sven Oehme
Sent: Wednesday, October 29, 2014 11:23 AM
To: gpfsug main discussion list
Subject: Re: [gpfsug-discuss] Server lost NSD mappings
 
if you still have a running system you can extract the information and 
recreate the descriptors. 
if your sytem is already down, this is not possible any more. 
 
which is why i suggested to open a PMR as the Support team will be able to 
provide the right guidance and help . 
 
Sven
 
On Wed, Oct 29, 2014 at 10:19 AM, Jonathan Buzzard <jonathan at buzzard.me.uk
> wrote:
On Wed, 2014-10-29 at 09:42 -0700, Sven Oehme wrote:
> Hello,
>
>
> there are multiple reasons why the descriptors can not be found .
>
>
> there was a recent change in firmware behaviors on multiple servers
> that restore the GPT table from a disk if the disk was used as a OS
> disk before used as GPFS disks.  some infos
> here : 
https://www.ibm.com/developerworks/community/forums/html/topic?id=27f98aab-aa41-41f4-b6b7-c87d3ce87b9e

>
>
> if thats the case there is a procedure to restore them.

I have been categorically told by IBM in no uncertain terms if the NSD
descriptors have *ALL* been wiped then it is game over for that file
system; restore from backup is your only option.

If the GPT table has been "restored" and overwritten the NSD descriptors
then you are hosed.

JAB.

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

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