Daniel Mahoney wrote:
> We are looking into some unusual NFS behavior changes as we migrate from a
> 2.6.8 kernel to a 2.6.24 kernel.
>
> We have two server farms, each having a few dozen machines accessing a
> central NAS via NFS. For testing purposes we have a 2.6.8 machine and a
> 2.6.24 machine both running webmail, therefore making frequent NFS access
> to small files. When we look at the traffic from the 2.6.8 kernel we see
> what we consider to be a reasonably low amount of NFS traffic. The traffic
> also follows what appears to be a reasonable pattern: LOOKUP calls, ACCESS
> calls, READDIRPLUS calls, an occasional GETATTR call. I'd estimate that
> GETATTR calls make up 10-15% of the total NFS traffic.
>
> The same webmail app running on the 2.6.24 kernel generates a lot more NFS
> traffic, and it's not nearly as intuitive a pattern: dozens of GETATTR
> calls, on occasional LOOKUP, ACCESS, REMOVE, etc. I'd estimate that the
> GETATTR calls account for easily 90% of the total NFS traffic. Machines
> running this new kernel are placing a much higher load on the NAS and the
> internal network the NAS runs on than the machines running the older
> kernel do.
>
> We've reviewed the kernel change logs and noted a few comments on minor
> changes in the NFS code, but we haven't seen any comments that seem to
> explain this kind of change in NFS performance. Can anyone point me to a
> source of info on this? We'd love to migrate all the farm machines to the
> newer kernel, but until we get a handle on the change in NFS behavior we
> can't really move forward.
I don't know what has changed in NFS between 2.6.8 and 2.6.24, but the folks
at
linux-(E-Mail Removed) would. That is the mailing list of the NFS
developers. You should post your message there.
Larry
Linear Mode
