[gpfsug-discuss] GPFS Independent Fileset Limit

[Peinkofer, Stephan]

Dear Olaf,


I know that this is "just" a "support" limit. However Sven some day on a UG meeting in Ehningen told me that there is more to this than just

adjusting your QA qualification tests since the way it is implemented today does not really scale ;).

That's probably the reason why you said you see sometimes problems when you are not even close to the limit.


So if you look at the 250PB Alpine file system of Summit today, that is what's going to deployed at more than one site world wide in 2-4 years and

imho independent filesets are a great way to make this large systems much more handy while still maintaining a unified namespace.

So I really think it would be beneficial if the architectural limit that prevents scaling the number of independent filesets could be removed at all.


Best Regards,
Stephan Peinkofer

________________________________
From: gpfsug-discuss-bounces at spectrumscale.org <gpfsug-discuss-bounces at spectrumscale.org> on behalf of Olaf Weiser <olaf.weiser at de.ibm.com>
Sent: Friday, August 10, 2018 2:51 PM
To: gpfsug main discussion list
Cc: gpfsug-discuss-bounces at spectrumscale.org; Doris Franke; Uwe Tron; Dorian Krause
Subject: Re: [gpfsug-discuss] GPFS Independent Fileset Limit

Hallo Stephan,
the limit is not a hard coded limit  - technically spoken, you can raise it easily.
But as always, it is a question of test 'n support ..

I've seen customer cases, where the use of much smaller amount of independent filesets generates a lot performance issues, hangs ... at least noise and partial trouble ..
it might be not the case with your specific workload, because due to the fact, that you 're running already  close to 1000 ...

I suspect , this number of 1000 file sets  - at the time of introducing it - was as also just that one had to pick a number...

... turns out.. that a general commitment to support > 1000 ind.fileset is more or less hard.. because what uses cases should we test / support
I think , there might be a good chance for you , that for your specific workload, one would allow and support more than 1000

do you still have a PMR for your side for this ?  - if not - I know .. open PMRs is an additional ...but could you please ..
then we can decide .. if raising the limit is an option for you ..





Mit freundlichen Grüßen / Kind regards


Olaf Weiser

EMEA Storage Competence Center Mainz, German / IBM Systems, Storage Platform,
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From:        "Peinkofer, Stephan" <Stephan.Peinkofer at lrz.de>
To:        gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Cc:        Doris Franke <doris.franke at de.ibm.com>, Uwe Tron <utron at lenovo.com>, Dorian Krause <d.krause at fz-juelich.de>
Date:        08/10/2018 01:29 PM
Subject:        [gpfsug-discuss] GPFS Independent Fileset Limit
Sent by:        gpfsug-discuss-bounces at spectrumscale.org
________________________________



Dear IBM and GPFS List,

we at the Leibniz Supercomputing Centre and our GCS Partners from the Jülich Supercomputing Centre will soon be hitting the current Independent Fileset Limit of 1000 on a number of our GPFS Filesystems.

There are also a number of RFEs from other users open, that target this limitation:
https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=56780
Sign up for an IBM account<https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=56780>
www.ibm.com
IBM account registration



<https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=56780>https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=120534
https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=106530
https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=85282

I know GPFS Development was very busy fulfilling the CORAL requirements but maybe now there is again some time to improve something else.

If there are any other users on the list that are approaching the current limitation in independent filesets, please take some time and vote for the RFEs above.

Many thanks in advance and have a nice weekend.
Best Regards,
Stephan Peinkofer

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