[CentOS] nfs (or tcp or scheduler) changes between centos 5 and 6?

On Wed, Apr 29, 2015 at 10:51 AM,  <m.roth at 5-cent.us> wrote:
>> The server in this case isn't a Linux box with an ext4 file system - so
>> that won't help ...
>>
> What kind of filesystem is it? I note that xfs also has barrier as a mount
> option.

The server is a NetApp FAS6280.  It's using NetApp's filesystem.  I'm
almost certain it's none of the common Linux ones.  (I think they call
it WAFL IIRC.)

Either way, we do the NFS mount read-only, so write barriers don't
even come into play.  E.g., with your original example, if we unzipped
something, we'd have to write to the local disk.

Furthermore, in "low load" situations, the NetApp read latency stays
low, and the 5/6 performance is fairly similar.  It's only when the
workload gets high, and it turn this "aggressive" demand is placed on
the NetApp, that we in turn see overall decreased performance.

Thanks for the thoughts!