[lustre-discuss] quota distribution over OSTs

Thomas Roth t.roth at gsi.de
Fri Jun 21 07:43:08 PDT 2019

Hi all,

we have 294 OSTs (of 40 TB or 66 TB) in a 2.10.5 system.

There is a group "kp2" with 14GB of data, and I have given it 50G/60G soft/hard quota.

This has lead to a quota warning although obviously the soft limit was not yet hit.

Looking a 'lfs quota -v', I see a number of OSTs with *limits, e.g.

OST0002_UUID     68.13M*      -  68.13M       -       -       -       -       -
OST0003_UUID     6.054M*      -  6.054M       -       -       -       -       -
OST0004_UUID        28k*      -     28k       -       -       -       -       -
OST0022_UUID        140k       -     64M       -       -       -       -       -
OST0023_UUID          0k       -      0k       -       -       -       -       -
OST0024_UUID         29k       -     64M       -       -       -       -       -

I have removed the quota limits and set them again, now the overall quota is again clear, 14G < 50G.
The distribution of the quota over the OSTs seems to be the same as before, though.

I suppose I have not understood correctly the role of the qunit size? (In fact, I don't even know
where to look up that value.)

The manual has this on the topic:
> Therefore, when the quota is consumed on one OST (resp. MDT), the client may not be able to create
files regardless of the quota available on other OSTs (resp. MDTs).

This statement seems to indicate that my "kp2" group would not be able to write anything anymore,
already due to those OSTs like "OST0004_UUID   28k*  - 28k", but writing still works.

Any clues to clear my confusion?

Best regards

Thomas Roth
Department: Informationstechnologie

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