Craig, In another SHARE session, I seem to remember that if you need to have very communications high throughput then you do not want to use VSWITCHes. Instead you want to dedicate a connection to the OSA adapter.
(I am unable at the moment to find that presentation.) However, in Mario Held's presentation, where he is going through the performance characteristics of the various types of communications, there is a phrase that says "Use direct OSA for outside connection of demanding guests" Also in Rob van der Heij's presentation "Linux on z/VM Understanding CPU Usage," there is a section "Improving TSM Throughput." This presentation presents a case study. You might find it interesting. Ron Craig Collins wrote:
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 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 .
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