Hi, This is a production system so messing around with it for long is a problem. You want to see if a guest lan will be better than a disconnected VSWITCH? My MTU is 1492.
-----Original Message----- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of David Kreuter Sent: Wednesday, October 26, 2011 8:21 PM To: LINUX-390@VM.MARIST.EDU Subject: Re: z/VM Switch performance Hi Offer: try these scenarios: 1. keep the VSWITCH as DISCONNECT (i.e. no osa) and try your pings again 2. create a guest lan (not a VSWITCH), give the machines nic's to the guest lan and try again. what are your mtu sizes? regards David Kreuter > -------- Original Message -------- > Subject: z/VM Switch performance > From: Offer Baruch <offerbar...@gmail.com> > Date: Wed, October 26, 2011 1:49 pm > To: LINUX-390@VM.MARIST.EDU > > Hi all, > > > > I have a major problem with what seems as VSWITCH performance issue. > > I have a VLAN aware VSWITCH connected to 2 X 1Gb OSA ports (1 for > backup - no link aggregation). > > A continues ping between 2 Linux guest on the same VSWITCH on the same > VLAN will show high response times (meaning that all communication > between the 2 guests remain within the VSWITCH) > > Things like 200ms, 50ms, 8ms (not all the time but every 3 or 4 pings > I get a high one). > > A continues ping from the Linux guest to itself will show much less > than 1ms all the time. I conclude from that, that the Linux guest > itself is not the problem. > > It means that the Linux guest is dispatched, does not hang. It test > both the Linux responsiveness and the Linux tcpip stack. > > That leads to my conclusion that the only difference of the 2 tests is > the VSWITCH being involved. > > z/VM is far from 100% CPU and almost no paging is in place (10-15 > pages per second). > > I can't figure out what might be the problem. > > I did find 2 APARS talking about VSWITCH performance after a failover > to the backup device. > > The APAR states to disconnect and connect the OSA devices (I did SET > VSWITCH DISCONNECT followed by a SET VSWITCH CONNECT) but the problem remains. > > > > Linux guest are using Access NICs (that is not truck). > > > > Any ideas? > > > > Thanks > > Offer Baruch > > > ---------------------------------------------------------------------- > 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 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/ ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1411 / Virus Database: 2092/3975 - Release Date: 10/26/11 ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
