[Linux-cluster] Why GFS is so slow? What it is waiting for?

[Bob Peterson]

On Thu, 2008-05-08 at 14:27 -0700, Ja S wrote:
> Hi, All:
> 
> I used to post this question before, but have not
> received any comments yet. Please allow me post it
> again.
> 
> I have a subdirectory containing more than 30,000
> small files on a SAN storage (GFS1+DLM, RAID10). No
> user application knows the existence of the
> subdirectory. In other words, the subdirectory is free
> of accessing. 
> 
> However, it took ages to list the subdirectory on an
> absolute idle cluster node. See below:
> 
> # time ls -la | wc -l
> 31767
> 
> real    3m5.249s
> user    0m0.628s
> sys     0m5.137s
> 
> There are about 3 minutes spent on somewhere. Does
> anyone have any clue what the system was waiting for?
> 
> 
> Thanks for your time and wish to see your valuable
> comments soon.
> 
> Jas

Hi Jas,

I believe the answer to your question is in the FAQ:

http://sources.redhat.com/cluster/wiki/FAQ/GFS#gfs_slow

Regards,

Bob Peterson
Red Hat Clustering & GFS