m.roth@5-cent.us wrote:
Matt Garman wrote:
We have a "compute cluster" of about 100 machines that do a read-only NFS mount to a big NAS filer (a NetApp FAS6280). The jobs running on these boxes are analysis/simulation jobs that constantly read data off the NAS.
<snip> *IF* I understand you, I've got one question: what parms are you using to mount the storage? We had *real* performance problems when we went from 5 to 6 - as in, unzipping a 26M file to 107M, while writing to an NFS-mounted drive, went from 30 sec or so to a *timed* 7 min. The final answer was that once we mounted the NFS filesystem with nobarrier in fstab instead of default, the time dropped to 35 or 40 sec again.
barrier is in 6, and tries to make writes atomic transactions; its intent is to protect in case of things like power failure. Esp. if you're on UPSes, nobarrier is the way to go.
The server in this case isn't a Linux box with an ext4 file system - so that won't help ...
James Pearson