Hi Christian, Indeed I did expect to easily add disks to the machine. Our SUSE machines have a lot of DASD and run in pretty small machines. So I was very surprised to see this problem.
As for process, in top [kswapd0] showed the large CPU load. Also the memory in top showed all memory was full and the eventhough it's just an 'empty' machine there is swap space usage increased. I didn't list iotop, if anything I was already happy to be able to start top. But since [kswapd0] was the active process I assumed swapping is the cause of the high IO load. In z/VM I could see over 4000 IO/s on DASD (performance toolkit panel FCX115). Meanwhile I have moved the installed image from the installer (virtual storage 2GB) into the production configuration (virtual storage 32GB). Now I can activate disks without any problem, but it also shows why it was a problem in the installer system. After boot: (29 ECKD disks) Tasks: 136 total, 1 running, 60 sleeping, 0 stopped, 0 zombie KiB Mem : 32807736 total, 31001912 free, 1637604 used, 168220 buff/cache KiB Swap: 719852 total, 719852 free, 0 used. 30877584 avail Mem After chccwdev -e 1210-1226 (23 disks) Tasks: 136 total, 1 running, 60 sleeping, 0 stopped, 0 zombie KiB Mem : 32807736 total, 30170712 free, 2440336 used, 196688 buff/cache KiB Swap: 719852 total, 719852 free, 0 used. 30060900 avail Mem After chccwdev -e 110-116 (7 disks) Tasks: 126 total, 1 running, 60 sleeping, 0 stopped, 0 zombie KiB Mem : 32807736 total, 29904272 free, 2685212 used, 218252 buff/cache KiB Swap: 719852 total, 719852 free, 0 used. 29806820 avail Mem In all three cases the ps shows similar values: root@zlx-ml01:~# ps aux --sort -rss USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1001 0.0 0.0 98488 17108 ? Ssl 17:15 0:00 /usr/bin/python3 /usr/bin/networkd-dispatcher --run-sta root 402 0.0 0.0 34052 14716 ? S<s 17:15 0:00 /lib/systemd/systemd-journald root 1 0.5 0.0 13884 9320 ? Ss 17:15 0:00 /sbin/init nl24220 1223 0.0 0.0 12284 7100 ? Ss 17:15 0:00 /lib/systemd/systemd --user root 999 0.0 0.0 232708 6976 ? Ssl 17:15 0:00 /usr/lib/accountsservice/accounts-daemon root 438 0.0 0.0 1708396 5616 ? Ss 17:15 0:00 /sbin/lvmetad -f root 1009 0.0 0.0 9792 5576 ? Ss 17:15 0:00 /lib/systemd/systemd-logind root 1058 0.0 0.0 9904 5352 ? Ss 17:15 0:00 /usr/sbin/sshd -D So the with the primary disk configuration the machine already assigned 1.6GB, given the available memory in the installer system that was already too much. After I activated another 23 disks, the used memory is now 2.4GB and after activating another 7 disk it's 2.6GB. I do have the OOM list in /var/log/syslog but I am unsure what to look for. Met vriendelijke groet/With kind regards/Mit freundlichen Grüßen, Berry van Sleeuwen Flight Forum 3000 5657 EW Eindhoven -----Original Message----- From: Linux on 390 Port <[email protected]> On Behalf Of Christian Ehrhardt Sent: Thursday, November 07, 2019 4:07 PM To: [email protected] Subject: Re: Ubuntu 18-04 unable to add DASD On Thu, Nov 7, 2019 at 3:57 PM van Sleeuwen, Berry <[email protected]> wrote: > > Hi All, > > I have installed an Ubuntu 19-04 but as it turns out the application requires > version 18-04. So I have installed a new 18-04 system. > > Next I tried to move the LVM from the 19-04 machine into the 18-04 machine. > But I can't get the disks online. The first few disks are fine but at a > certain point the server crashes. During "chccwdev -e" at some point all > memory is exhausted and I see a lot of CPU and IO. Eventually the OOM-killer > kicks in to kill various processes. The server is no longer responding and > only a reboot (force and xautolog) will get the server back online. Hi Berry, I have myself enabled hundreds of dasds without such issues, so it must be something special to your system/config that we have to find out. We all know that chccwdev shouldn't do any I/O other than to the entries in /sys so I'm wondering what goes on. You said you have a lot of CPU+IO and then the OOM-killer kicks in. Can you outline a) which processes spin when being CPU intensive - gather with e.g. top in batch mode b) which processes drive that I/O - gather with iotop (btw - do you see that I/O in VM or in Linux) c) when the OOM killer kicks in (or if you can before) which processes consume huge chunks of memory? If you have nothing else, at least the OOM report that dmesg holds should have a list. >From there we can start to gather ideas what it might be. 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