[Beowulf] GPFS and failed metadata NSD
John Hanks
griznog at gmail.com
Sat Apr 29 09:13:10 PDT 2017
There are no dumb questions in this snafu, I have already covered the dumb
aspects adequately :)
Replication was not enabled, this was scratch space set up to be as large
and fast as possible. The fact that I can say "it was scratch" doesn't make
it sting less, thus the grasping at straws.
jbh
On Sat, Apr 29, 2017, 7:05 PM Evan Burness <evan.burness at cyclecomputing.com>
wrote:
> Hi John,
>
> I'm not a GPFS expert, but I did manage some staff that ran GPFS
> filesystems while I was at NCSA. Those folks reeeaaalllly knew what they
> were doing.
>
> Perhaps a dumb question, but should we infer from your note that metadata
> replication is not enabled across those 4 NSDs handling it?
>
>
> Best,
>
> Evan
>
>
> -------------------------
> Evan Burness
> Director, HPC
> Cycle Computing
> evan.burness at cyclecomputing.com
> (919) 724-9338
>
> On Sat, Apr 29, 2017 at 9:36 AM, Peter St. John <peter.st.john at gmail.com>
> wrote:
>
>> just a friendly reminder that while the probability of a particular
>> coincidence might be very low, the probability that there will be **some**
>> coincidence is very high.
>>
>> Peter (pedant)
>>
>> On Sat, Apr 29, 2017 at 3:00 AM, John Hanks <griznog at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I'm not getting much useful vendor information so I thought I'd ask here
>>> in the hopes that a GPFS expert can offer some advice. We have a GPFS
>>> system which has the following disk config:
>>>
>>> [root at grsnas01 ~]# mmlsdisk grsnas_data
>>> disk driver sector failure holds holds
>>> storage
>>> name type size group metadata data status
>>> availability pool
>>> ------------ -------- ------ ----------- -------- ----- -------------
>>> ------------ ------------
>>> SAS_NSD_00 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_01 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_02 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_03 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_04 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_05 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_06 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_07 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_08 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_09 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_10 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_11 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_12 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_13 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_14 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_15 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_16 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_17 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_18 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_19 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_20 nsd 512 100 No Yes ready up
>>> system
>>> SAS_NSD_21 nsd 512 100 No Yes ready up
>>> system
>>> SSD_NSD_23 nsd 512 200 Yes No ready up
>>> system
>>> SSD_NSD_24 nsd 512 200 Yes No ready up
>>> system
>>> SSD_NSD_25 nsd 512 200 Yes No to be emptied
>>> down system
>>> SSD_NSD_26 nsd 512 200 Yes No ready up
>>> system
>>>
>>> SSD_NSD_25 is a mirror in which both drives have failed due to a series
>>> of unfortunate events and will not be coming back. From the GPFS
>>> troubleshooting guide it appears that my only alternative is to run
>>>
>>> mmdeldisk grsnas_data SSD_NSD_25 -p
>>>
>>> around which the documentation also warns is irreversible, the sky is
>>> likely to fall, dogs and cats sleeping together, etc. But at this point I'm
>>> already in an irreversible situation. Of course this is a scratch
>>> filesystem, of course people were warned repeatedly about the risk of using
>>> a scratch filesystem that is not backed up and of course many ignored that.
>>> I'd like to recover as much as possible here. Can anyone confirm/reject
>>> that deleting this disk is the best way forward or if there are other
>>> alternatives to recovering data from GPFS in this situation?
>>>
>>> Any input is appreciated. Adding salt to the wound is that until a few
>>> months ago I had a complete copy of this filesystem that I had made onto
>>> some new storage as a burn-in test but then removed as that storage was
>>> consumed... As they say, sometimes you eat the bear, and sometimes, well,
>>> the bear eats you.
>>>
>>> Thanks,
>>>
>>> jbh
>>>
>>> (Naively calculated probability of these two disks failing close
>>> together in this array: 0.00001758. I never get this lucky when buying
>>> lottery tickets.)
>>> --
>>> ‘[A] talent for following the ways of yesterday, is not sufficient to
>>> improve the world of today.’
>>> - King Wu-Ling, ruler of the Zhao state in northern China, 307 BC
>>>
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>>
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>
>
> --
> Evan Burness
> Director, HPC Solutions
> Cycle Computing
> evan.burness at cyclecomputing.com
> (919) 724-9338
>
--
‘[A] talent for following the ways of yesterday, is not sufficient to
improve the world of today.’
- King Wu-Ling, ruler of the Zhao state in northern China, 307 BC
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