Offer, I do get the erratic pings too. Not as high as 200, but some 50s. It was reported to me a few weeks ago by one of our more sophisticated users that traceroute occasionally fails over the same vswitch. Run it like 20 times 1 right after another to recreate or use the -q option with something like -q 8.
I checked with another customer and he also saw the same behavior. I opened a PMR with VM but they said to open one with Linux. I have not gotten around to opening one with Novell yet. Could some of you others out there try this simple ping test? We are also vlan aware and it does happen on both LACP and non-LACP. Marcy This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation. -----Original Message----- From: Linux on 390 Port [mailto:LINUX-390@vm.marist.edu] On Behalf Of David Kreuter Sent: Thursday, October 27, 2011 3:48 AM To: LINUX-390@vm.marist.edu Subject: Re: [LINUX-390] z/VM Switch performance Yes I would like to see how a guest lan behaves. Can you send a sample of the pings with the erratic response times? David -------- Original Message -------- Subject: Re: z/VM Switch performance From: Offer Baruch <offerbar...@gmail.com> Date: Thu, October 27, 2011 5:19 am To: LINUX-390@VM.MARIST.EDU 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/ ---------------------------------------------------------------------- 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/
