[CentOS] gfs performance

[sophana]

I haven't tried gfs yet, but did you simply test simultaneous access to 
the same local disk (without gfs) by 2 separate processes: generally 
peformance drops because of disk seek time (the reason is mechanical)
Disks always have much lower performance when shared between 2 processes 
on the same machine or 2 processes on separate machines (it is the same 
as having a dual cpu)

This is just an idea... not very sure if this is your problem.

Jure Pečar wrote:

>Hi all,
>
>Since I've got no reply on redhat cluster list, I'm trying here ...
>
>I'm testing a rhcs4 cluster with gfs. I noticed some poor performance while
>tarring data from a gfs volume to a local disk from both nodes at the same
>time, so I deceided to have a closer look.
>
>Here are the bonnie++ results: http://jure.pecar.org/gfs/
>
>I don't know what to think of these ... but I doubt it's normal for
>performance to go down by an order of magnitude when both nodes are doing
>some i/o to the shared file system ... 
>
>I'd like to see some numbers from other gfs systems to see if this is
>normal and if it is not, how to figure out what's wrong and how to fix it.
>
>Thanks,
>
>
>  
>