On Monday, 10/26/2009 at 04:21 EDT, "Harder, Pieter" <pieter.har...@brabantwater.nl> wrote: > For the finer points of performance measurement I defer to Rob. This is a > highlevel coarse view: > With a VSWITCH with LACP involved and using two full IFL's with 4 OSA GbE I > could barely exceed 100 MB/s with no other activity at all. With the same 2 > IFL's and 4 OSA dedicated and bonded within Linux I have seen 175 MB/s with > other activity going on.
Do you have statistics for packets on each interface in the port group? If you read "Load Balancing within the Virtual Switch" in the z/VM Connectivity book, you will discover that load balancing takes place on a per-"conversation" basis, where a "conversation" is defined as a unique pairing of (vnic origin MAC, dest MAC). Since most guests on a VSWITCH will tending to speak to the same host (the gateway), the destination MAC can be considered a constant. Consequently, you will only see the load balancing in action when you have multiple VNICs in the guest or multiple guests. This means that a single virtual NIC on a single guest is still limited to a single OSA, so any single-guest performance measurement of LACP-enabled VSWITCH can give misleading results as to the capacity of the VSWITCH as a whole. (Physical switches have multiple load balancing algorithms to choose from.) The z/VM Performance Report contains IBM analysis of Link Aggregation. Alan Altmark z/VM Development IBM Endicott ---------------------------------------------------------------------- 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
