We are just starting to use OSA-Express3 10 Gb ports for SLES10-SP2 Linux
guests.  We're trying to use these with TSM servers running on SLES10 to
backup other non-zSeries servers in our environment.  We are using the 10 Gb
OSAs connected to VSWITCHes in zVM 5.4.  Currently we have only one SLES10
TSM server connected to a VSWITCH that is the only thing connected to a 10
Gb OSA and are seeing throughput of less than 1 Gb/s.  The Cisco switch the
OSA port is connected to recognizes the speed as 10 Gb.  The TSM server and
all of the servers it is backing up are on the same subnet and there is no
firewall involved.

Thanks to linuxvm.org, we found Share presentation 2192 by Mario Held from
August 2009 named "Linux on System z Performance Update - Part 2: Networking
and Crypto" which we found helpful and we have altered some of our settings
based upon the recommendations.  We also have been over the OSA and Vswitch
documentation from IBM looking for any speed settings related to this type
of OSA card, a VSWITCH, or a nic definition for a linux guest on zVM, but
did not find anything.

We still are not getting throughput we expect (or maybe desire).  We
wondered if a nic setting in SLES10 could be keeping the connection from
getting above the 1 Gb/s mark, but cannot find a parameter to change as the
normal parameters with ethtool don't seem to apply in this environment.

Is anyone else using a 10 Gb OSA through a VSWITCH and getting throughput
greater than 1 Gb for a single server instance?  If so, are there any
settings you needed to change to get to that performance level?  Or is there
a maximum of around 1 Gb that a single server instance can achieve?  We're
grasping at straws at this point.  Any ideas are appreciated.

Craig Collins
State of WI, DOA, DET

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