Quota performance hit?

Quota performance hit?

[David Shaw]

Hello,

I wonder if anyone could point me towards any numbers on how much of a performance penalty project quotas incur on a write-heavy filesystem.  The idea being discussed here is putting a project quota on the /var/log directory (so pretty write-heavy) to prevent it from overflowing /var, and thus causing problems for /var/lib, /var/tmp, and other things in /var that need some headroom.  The alternative is to simply use two different filesystems for /var and /var/lib.

Any information or pointers would be welcome.

Thanks,

David

Re: Quota performance hit?

[Dave Chinner]

On Wed, Jan 03, 2018 at 12:02:13AM -0500, David Shaw wrote:
> Hello,
> 
> I wonder if anyone could point me towards any numbers on how much
> of a performance penalty project quotas incur on a write-heavy
> filesystem.  The idea being discussed here is putting a project
> quota on the /var/log directory (so pretty write-heavy)

/var/log is definitely a "mostly write" directory, but I wouldn't
ever classify it as "write heavy".

Unless you are trying to perform thousands of concurrent writes
and/or log file creation/removal operations every second to
/var/log, then putting a project quota on that directory is not
going to cause you any sort of noticable problem.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: Quota performance hit?

[David Shaw]

On Jan 3, 2018, at 1:43 AM, Dave Chinner <david@fromorbit.com> wrote:
> 
> On Wed, Jan 03, 2018 at 12:02:13AM -0500, David Shaw wrote:
>> Hello,
>> 
>> I wonder if anyone could point me towards any numbers on how much
>> of a performance penalty project quotas incur on a write-heavy
>> filesystem.  The idea being discussed here is putting a project
>> quota on the /var/log directory (so pretty write-heavy)
> 
> /var/log is definitely a "mostly write" directory, but I wouldn't
> ever classify it as "write heavy".
> 
> Unless you are trying to perform thousands of concurrent writes
> and/or log file creation/removal operations every second to
> /var/log, then putting a project quota on that directory is not
> going to cause you any sort of noticable problem.

Excellent.  Sounds like I have nothing to worry about.

Thanks,

David