[Linux-cluster] Is nit worth setting up jumbo Ethernet frames on the cluster interconnect link?

[Steven Whitehouse]

Hi,

On Fri, 2010-04-02 at 11:26 +0000, Jankowski, Chris wrote:
> Hi,
>  
> On a heavily used cluster with GFS2 is it worth setting up jumbo
> Ethernet frames on the cluster interconnect link?  Obviously, if only
> miniscule portion of the packets travelling through this link are
> larger than standard 1500 MTU then why to bother.
>  
> I am seeing significant traffic on the link up to 50,000 packets per
> second.
The answer is probably not. Unless there is an application using the
link other than clustering, you are unlikely to improve matters a great
deal. The important thing is latency so far as locking traffic goes, not
the overall throughput. If you have issues with lots of network traffic,
that might indicate contention problems on certain inodes, and that can
usually be solved by looking carefully at how the application(s) use the
filesystem rather than by altering the networking side of things.

If on the other hand you are using iSCSI and/or exporting the GFS2
filesystem via NFS, then using jumbo frames might be an option worth
exploring,

Steve.