[Beowulf] NFS+XFS+SMP on kernel 2.6

David Kewley kewley at gps.caltech.edu
Wed Jun 15 11:11:45 PDT 2005

On Wednesday 15 June 2005 09:27, Joe Landman wrote:
> Suvendra Nath Dutta wrote:
> > We set up a 160 node cluster with a dual processor head node with
> > 2GB RAM. The head node also has two RAID devices attached to two
> > SCSI cards. These have a XFS filesystem on them and are NFS
> > exported to the cluster. The head node runs very low on memory (7-8
> > MB). And today I ran into a kernel bug that crashed the system.
> > Google suggests that I should upgrade to kernel 2.6.11, but that
> > sounds very unpleasant. I am thinking of putting the raid boxes on
> > a different box. Will separating the file-server and the head node
> > give me back stability on the head node?
>    What distribution are you using today?   Which kernel?
> what does your uasge pattern look like on the head node and on the
> file server?

And I would add: What processors?  (If that's not already implicit in 
"Which kernel?")

There are reports of nfs-exported xfs being unstable *if* you have x86 
and are running recent RH kernels, which have 4k kernel stacks.  The 
problem is that xfs tends to use a bunch of stack space, and if other 
kernel modules like nfs are used with xfs to access a filesystem, then 
the stack can overflow & crash the kernel.


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