Re: Elastic Quota File System (EQFS)

[Olaf Dabrunz]

On 25-Jun-04, Timothy Miller wrote:
> 
> I have a much simpler idea that both implements the EQFS and doesn't 
> touch the kernel.
> 
> Each user is given a quota which applies to their home directory.  (This 
> quota is not elastic and if everyone met their quota, everything would 
> fit.)  In addition, there is another directory or file system (could be 
> on the same disk or even the same partition) to which their quota 
> doesn't apply AT ALL.  Let's call this "scratch" space.
> 
> Periodically, a daemon checks the disk usage, and whenever the disk 
> usage approaches, say, 90%, its starts deleting the oldest files from 
> the scratch space until its gets below the watermark.
> 
> So anything in "/scratch/$USER/" is free to be deleted by the daemon.
> 
> BTW, they did something similar to this when I was in college (I 
> graduated in 1996), although they deleted from /scratch manually.

An easy setup for this is to put /home on a different filesystem than
/tmp, use quota on /home but leave quota off for /tmp. Then most Unix
systems can easily be configured to clean up /tmp periodically, and also
the user is easily aware of the nature of files in /tmp (i.e. they are
"elastic" in some sense).

My university was (and still is) using this setup on many servers.

-- 
Olaf Dabrunz (od/odabrunz), SUSE Linux AG, NÃrnberg

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