Thanks Ken. IBM responded back on this pmr. Lvl 2 suggested that the SRM values be changed to allow the Linux guests to remain in Q1(runnable,dispatchable).
Using Set SRM STORBUF 300 250 200 the SRM STORBUF were changed to: IABIAS : INTENSITY=90%; DURATION=2 LDUBUF : Q1=100% Q2=75% Q3=60% STORBUF: Q1=300% Q2=250% Q3=200% DSPBUF : Q1=32767 Q2=32767 Q3=32767 DISPATCHING MINOR TIMESLICE = 5 MS MAXWSS : LIMIT=9999% ...... : PAGES=999999 XSTORE : 0% According to Lvl2, this should allow the 4 Blaze instances to be active concurrently. "Hall, Ken (IDS ECCS)" wrote: > We've seen something like this, not exactly the same. We have an open issue with > IBM, but we're having trouble pinning it down. It originally started in zVM 4.2, > and seems to be better in 4.3, but > not completely resolved. > > In 4.2, we had Linux instances on guest LAN, where SOME, but not all of them would > consistently have terrible performance in and out. Changing IP addresses often > moved or relieved the problem. IBM > ultimately determined that packets were being dropped, but never found the cause. > It did seem to be related to the number of hosts on a LAN though, and might have > been aggravated by some > misconfiguration of the guest LAN and TCPIP. We upgraded VM to 4.3, reconfigured > the network somewhat, moved the Linux machines over intact, and the problem went > (mostly) away. > > On 4.3, we haven't seen anything as serious, but we do occasionally see situations > where a Linux guest will be running for a few days, and suddenly performance on the > LAN connection will drop WAY off. > Ping times, normally less than 1 ms., will increase to 500-1000 ms. or worse between > guests on the SAME LAN. Usually, the problem is limited to one guest at a time, so, > for example, with guests A, B, > and C, A will be affected, so ping between A&B and A&C (both ways) will be slow, but > ping between B&C will not. > > Rebooting the instance (without logging off) clears up the problem, leading me to > believe it might be something in the qeth or qdio drivers. This DOESN'T seem to be > related to the number of guests, > more to traffic. It happens most often on our production LDAP server, and > occasionally on production Samba servers. I've seen it on my test instance also, > when I'm running ssh or telnet. > > The VM guys here have been trying to get IBM to provide some tools for monitoring > the guest LAN. We've gotten some data using TCPDUMP on the guests, but the SuSE > SLES8 drivers broke that. IBM > provided a circumvention, and the fix for that will be in SP3, along with fixes to > the qeth drivers for some other problems we found. > > > -----Original Message----- > > From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of > > Marcy Cortes > > Sent: Tuesday, October 14, 2003 1:07 PM > > To: [EMAIL PROTECTED] > > Subject: Re: [LINUX-390] Ring Around The Guest Lan > > > > > > I have 17 connected to one right now and haven't seen > > anything like you're > > seeing either. Do you have current maintenance on z/VM? What is the > > MAXCONN setting on the guest lan (Q LAN DETAILS)? > > > > PS. What's BLAZE? > > > > Marcy Cortes > > Wells Fargo Services Company > > > > -----Original Message----- > > From: Post, Mark K [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, October 14, 2003 09:36 > > To: [EMAIL PROTECTED] > > Subject: Re: [LINUX-390] Ring Around The Guest Lan > > > > > > Ann, > > > > I have 8+ SLES7 Linux/390 guests hooked to one Guest LAN on a > > test box, and > > have not seen anything like that. Sorry. > > > > > > Mark Post > > > > -----Original Message----- > > From: Ann Smith [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, October 14, 2003 12:33 PM > > To: [EMAIL PROTECTED] > > Subject: Ring Around The Guest Lan > > > > > > We implemented a Guest Lan on our linux POC machine last week. > > We are running 1 linux guest with WBIMB 5.0 (MQSI) , 1 guest > > with Blaze > > persistence mgr and Oracle data base, 1 guest running Blaze > > and MQ queue > > mgr., > > and 3 other Blaze guests. Anyway, when the 4th linux guest attempts to > > bring up Blaze the strangeness begins. We start losing connectivity > > randomly to the linux guests. The linux guests do not go down but > > something is very wrong. You can watch the connectivity failures move > > from guest to guest. They are back then they are gone. I am still > > waiting for the Blaze folks to tell me what messages the 4th guests > > received. The Blze startup seems to have failed. So far we took a VM > > restart dump and sent it off to IBM. But I figured I'd ask if > > anyone has > > seen a similar situation. We only have 1 more week with our loaner > > hardware for our linux POC. We are running z/VM 4.3 and SuSE SLES8 (31 > > bit). > >
