[Lustre-discuss] Line rate performance for clients

Brock Palen brockp at umich.edu
Fri Jul 29 10:33:10 PDT 2011

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
Center for Advanced Computing
brockp at umich.edu

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