>From a Z terminology point of view this 'multipath with DASD' feature, is >officially known as 'HyperPAV' (the improved version of PAV, the Parallel >Access Volumes feature). (Btw. for the former 'PAV' feature multipath-tools were indeed needed for the setup.) It's an option that allows to increase disk IO performance under certain circumstances. Well, even a single disk system can benefit from it - however most benefits are given in case larger amounts of DASD disks are in use with lot's of IO in parallel and with large caches, striping and more implemented at the disk sub-system (which is barely the case in our environment). The benfits in this case (system with single disk, in this particular environment) are not expected to be huge. Otohs the DASD driver will consume more memory due to the additional alias disks and their queues. Hence I assume (agree) that the reboot didn't entirely hang, but was indeed significantly delayed. And the more DASDs (incl. alias) were active, the longer the delay (but needs validation).
I'm checking the base and alias subchannels definition as well as the ranges and will do some more tests on a different LPAR, and will also check the status of the FICON adapters, especially double checking if any CU resources are exceeded (what we had in the past). It's here save and recommended to run w/o the alias devices activated. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1855237 Title: Extreme Delayed Reboot with Disco on Ubuntu LPAR s390x (5.0.0-38) Status in Ubuntu on IBM z Systems: Triaged Status in linux package in Ubuntu: Triaged Bug description: With the proposed Disco kernel (5.0.0-38) I can't reboot the s390x LPAR node s2lp4 When I tried to reboot the system it will render the system into a "Not operating" status. I tried to watch the output from the Integrated ASCII console and the Operating system messages from IBM Hardware Management Console. But there is nothing interesting there From Operating System Messages, it ends at: [ OK ] Reached target Final Step. [ OK ] Started Reboot. [ OK ] Reached target Reboot. And never proceed from this point. And HMC shows "Not operating" From Integrated ASCII console it just shows the login prompt, never prints any other message. Reboot works fine with older kernel (5.0.0-37) ProblemType: Bug DistroRelease: Ubuntu 19.04 Package: linux-image-5.0.0-38-generic 5.0.0-38.41 ProcVersionSignature: Ubuntu 5.0.0-38.41-generic 5.0.21 Uname: Linux 5.0.0-38-generic s390x NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair AlsaDevices: Error: command ['ls', '-l', '/dev/snd/'] failed with exit code 2: ls: cannot access '/dev/snd/': No such file or directory AplayDevices: Error: [Errno 2] No such file or directory: 'aplay': 'aplay' ApportVersion: 2.20.10-0ubuntu27.4 Architecture: s390x ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord': 'arecord' CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found. Date: Thu Dec 5 06:46:12 2019 HibernationDevice: RESUME=UUID=eae923f9-f5a4-41c0-b3e4-04786207dbaa IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig': 'iwconfig' Lsusb: Error: command ['lsusb'] failed with exit code 1: PciMultimedia: ProcFB: ProcKernelCmdLine: root=UUID=1a6af794-84a9-4034-a213-39506b9bb91c crashkernel=196M BOOT_IMAGE=0 RelatedPackageVersions: linux-restricted-modules-5.0.0-38-generic N/A linux-backports-modules-5.0.0-38-generic N/A linux-firmware 1.178.6 RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1855237/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
