We've been in the land of WAS since WAS 5! Everything was just peachy until this kernel.
One server was 1500M with 2 apps each with a heap size of 1024 and a dmgr and a node agent. He was even ok until this! I'm surprised it ran at all. (Note, dev/test, not prod. We wouldn't do that to prod :). Marcy -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Dean, David (I/S) Sent: Monday, November 04, 2013 5:43 AM To: [email protected] Subject: Re: [LINUX-390] SLES 11 SP3 problems Welcome to WAS, Dorothy. We have been running WAS since WAS 6 on SLES 8. I cannot give you answers (then why the heck are you writing??) but I can give several well experienced situations we have had. 1. "Upping the memory solves it", you are correct - the opposite of everything we have learned. I was privy to an internal memo from IBM explaining the z10 actually has a whole bunch of Intel processors hidden inside, and if you will just reboot it, all will be fine. 2. Yep, too low the memory, you get this nice loop, and eventually, although not frequent anymore, all the other little puppies start fighting for milk ( resources) and slowly and surely we would end up with 10 maxed servers. And, yes, this was after I swore to the entire Demand Management Department that no one zLinux box could ever effect the others - got to stop reading those darn IBM pamphlets... I am open to the scenario that I don't know the settings that would stop this behavior. 3. Heap Size. WAS is not good at sharing the memory assigned to its heap size. It is almost (but not) as if it reads the heap size definition in WAS and thinks it HAS to have that amount. We do not have to equal it, but we do have to over allocate memory. 4. I am amazed that you are able to even get a 1 gig WAS server up. At a recent DR exercise, it was decided (singly) that we could use half the memory on a second level system and it would be fine. After over 3 hours of watching a WAS startup screen I was called at 4 AM and asked to come in and fix? WAS? And you know, I have no idea if that was a loop (broken) or just little WAS bashing his 25 server head trying to get everybody up. I am smart enough to realize that I have added nothing to the answers and all to the questions, but I am hoping some wiser minds will weigh in on the discussion. zVM 6.2 SUSE 11.2 Z10 Velocity Monitor -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Marcy Cortes Sent: Friday, November 01, 2013 3:55 PM To: [email protected] Subject: Re: SLES 11 SP3 problems This may trigger it on a 1G server perl -e '$num=50_000_000; @a=(0..$num); foreach $j (0..4) { $a[$_] = $_ foreach (0..$num); $|=1; print "Done with pass $j at", `date` ; } print "Done\n"' (thanks to my colleague Ted for figuring that out). -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Marcy Cortes Sent: Friday, November 01, 2013 12:50 PM To: [email protected] Subject: Re: [LINUX-390] SLES 11 SP3 problems No, all shows up in system. -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Ron Foster Sent: Friday, November 01, 2013 12:34 PM To: [email protected] Subject: Re: [LINUX-390] SLES 11 SP3 problems Is there a particular process using all the time? Sent from my iPhone On Nov 1, 2013, at 12:31 PM, "Marcy Cortes" <[email protected]> wrote: > We're experiencing a problem with kernel 3.0.93 (SP3). It seems on servers > that are memory constrained can go into a loop doing tons of i/o - 8000+ / > second. > It seems to happen with things like WAS deploys. We may have also been > able to recreate use a simple perl array. > > Has anyone else seen this? > > Yes, we have a high priority SR opened with SUSE. > > Oddly we have seen something like this after a kernel update on SP2. That > was solved by changing vm.swappiness to something > 0. We have put it back > to 60 (the default) and still get the problem. > Upping the memory solves it, but obviously, that's not something we want to > be doing, especially in our constrained dev environment. > > > Marcy > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, send > email to [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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/ ----------------------------------------------------- Please see the following link for the BlueCross BlueShield of Tennessee E-mail disclaimer: http://www.bcbst.com/email_disclaimer.shtm ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] 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 [email protected] 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/
