[Lustre-discuss] Line rate performance for clients

[Brock Palen]

I think this is a networking question.

We have lustre 1.8 clients with 1gig-e interfaces that according to ethtool are running full duplex.

If I do the following:

cp /lustre/largeilfe.h5 /tmp/

I get 117MB/s

If I then use globus-url-copy to move that file from /tmp/ to -> remove tape archive I get 117MB/s

If I go directly from  /lustre -> archive  I get 50MB/s,  

this is consistently reproducible.  It doesn't mater if I just copy a large file on lustre to lustre,  or scp, or globus.  If I try to ingest and outgest data I get what looks like half duplex performance. 

Anyone have ideas why I cannot do 1Gig-e full duplex?

Brock Palen
www.umich.edu/~brockp
Center for Advanced Computing
brockp at umich.edu
(734)936-1985