[CentOS] OT how to prevent oversubscription of a disk

Tue Jan 4 01:27:02 UTC 2011
Peter Brady <pdbrady at ans.com.au>

On 4/01/11 6:39 AM, Dave wrote:
> I agree that some degree of oversubscription is probably desireable,
> and it would be much easier to just add storage whenever it looks to
> be getting fullish. My situation right now makes that difficult -
> budget is gone, so I can't add storage, and my users sometimes start
> up a big simulation that could potentially fill the disk right before
> the weekend. If the hoggy simulation crashes itself, that's okay, but
> if it brings down a lot of other jobs submitted by other users, I look
> bad. I guess even if there was some good tool support, this task is
> doomed to make everyone unhappy.

I have a similar problem with ANSYS users in an HPC environment, in that 
un-schooled ANSYS users can generate vast quantities of (garbage) data 
very quickly.  For some of these users that seem particularly unable to 
learn how to use ANSYS I've spun their home directories off to 
individual partitions.  That way they only crash themselves and there is 
a very definite hard limit on what they can fill.

Perhaps not as elegant as quotas but it sure works.

I don't run quotas per say but monitor users under a kind of "fair use" 
policy.  Just have a df based script that runs once a day.  The vast 
majority of my users don't generate much data so I'd be really over 
subscribed.  Its the small number of FEA and CFD users that fill my drives.

Still, its a big task to continually educate and remind users on the 
appropriate etiquette when using shared resources.