[CentOS] GFS and Small Files

William L. Maltby CentOS4Bill at triad.rr.com
Wed Apr 29 13:35:07 UTC 2009


On Wed, 2009-04-29 at 19:01 +0800, Hairul Ikmal Mohamad Fuzi wrote:
> Hi all,
> 
> We are running CentOS 5.2 64bit as our file server.
> Currently, we used GFS (with CLVM underneath it) as our filesystem
> (for our multiple 2TB SAN volume exports) since we plan to add more
> file servers (serving the same contents) later on.
> 
> The issue we are facing at the moment is we found out that command
> such as 'ls' gives a very slow response.(e.g 3-4minutes for the
> outputs of ls to be printed out, or in certain cases, 20minutes or so)
> This is completely true especially in directories containing "large
> number" of small files (e.g 90000+ of 1-4kb files). The thing is, most
> of system users are generating these small files frequently as part of
> their workflow.

One thing to keep in mind is that ls must sort the file list. If the
system load is high and memory is short, you may be getting into a swap
situation. I suggest trying the test when the system is lightly loaded
to see if the results differ. This might be especially significant if
you have a large number of concurrent users doing lots of things.

As well (I believe this is not FUD), 64 bit systems use more memory
inherently so memory shortage problems could be exacerbated.

> <snip>

You might want to check and see if swap is heavily used (if not
root, /sbin/swapon -s). That might be helpful, or not.

> TIA.
> 
> .ikmal
> <snip sig stuff>

HTH
-- 
Bill



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