[gpfsug-discuss] Odd behaviour with regards to reported free space

[Jonathan Buzzard]

On Tue, 2020-02-18 at 09:28 +0000, TURNER Aaron wrote:
> Dear All,
>  
> This has happened more than once with both 4.2.3 and 5.0. The
> instances may not be related.
>  
> In the first instance, usage was high (over 90%) and so users were
> encouraged to delete files. One user deleted a considerable number of
> files equal to around 10% of the total storage. Reported usage did
> not fall. There were not obviously any waiters. Has anyone seen
> anything similar?
> 

I have seen similar behaviour a number of times.

I my experience it is because a process somewhere has an open file
handle on one or more files/directories. So you can delete the file and
it goes from a directory listing; it's no long visible when you do ls.

However the file has not actually gone, and will continue to count
towards total file system usage, user/group/fileset quota's etc.

Once the errant process is found and killed magically the space becomes
free.

I can be very confusing for end users, especially when what is holding
onto the file is some random zombie process on another node that died
last month.


JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG