[Pvfs2-users] Performance Problems

[belcampo]

Jim Kusznir wrote:
> Hi all:
> 
> I've been trying to track down some performance problems with my pvfs2
> system on my HPC cluster.  Here's my system arch:
> 
> I have 3 dedicated I/O nodes, each are identical Dell PowerEdge 1950's
> with PERC 6/e cards attached to a 15-disk MD1000 that has about 9.8TB
> of storage after RAID-6'ing it.
> Each I/O node has both of its Gig-E interfaces connected to the
> cluster's switch and bonded together (bond0).  The systems are running
> CentOS 5 and the RAID is formatted with XFS.
> bonnie++ on one of the raid disk (locally) reports:
Getting more or less decent I/O for more or less average applications it 
helps to export the pvfs filesystem over nfs.
Let me explain, playing a video with mplayer from the pvfs file-system 
is impossible, it stop/starts continuously, not useable.
If pvfs is exported and play the same file via the nfs-mount it plays 
OK. It's a matter of the 'right' buffering for that 'average' 
application, which nfs in this case does, that makes the difference in 
this case.