Today I did some more tests and investigations. First of all I moved to the new mantic ISO image (20230928) that improved things quite a lot! The installation (on z/VM so far) is again very snappy and quick, incl. the enablement of a DASD device in the zDev activation screen. At the end of the installation, before hitting 'Reboot now' I went to the console and had a look at top to see if udev related processes are active, but I couldn't identify any: top - 10:47:51 up 9 min, 2 users, load average: 0.44, 0.41, 0.20 Tasks: 137 total, 1 running, 136 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st MiB Mem : 3988.9 total, 214.3 free, 1957.6 used, 3233.2 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 2031.3 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 15026 root 20 0 8788 4864 2816 R 0.7 0.1 0:00.28 top 1439 root 20 0 129824 74216 21376 S 0.3 1.8 0:03.76 /snap/subiquity/5183/usr/bin/python3.10 /snap/subiquity/518+ 1441 root 20 0 129788 74312 21376 S 0.3 1.8 0:03.57 /snap/subiquity/5183/usr/bin/python3.10 /snap/subiquity/518+ 2381 root 20 0 12216 5760 4864 S 0.3 0.1 0:00.10 sudo snap run subiquity 2383 root 20 0 206204 77680 21632 S 0.3 1.9 0:04.96 /snap/subiquity/5183/usr/bin/python3.10 -m subiquity 1 root 20 0 103300 13676 8940 S 0.0 0.3 0:03.49 /sbin/init --- 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [kthreadd] 3 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [rcu_gp] 4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [rcu_par_gp] 5 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [slub_flushwq] 6 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [netns] 8 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [kworker/0:0H-events_highpri] 9 root 20 0 0 0 0 I 0.0 0.0 0:00.00 [kworker/0:1-cgroup_destroy] 10 root 20 0 0 0 0 I 0.0 0.0 0:01.11 [kworker/u128:0-events_unbound] 11 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 [mm_percpu_wq] 12 root 20 0 0 0 0 I 0.0 0.0 0:00.00 [rcu_tasks_rude_kthread] 13 root 20 0 0 0 0 I 0.0 0.0 0:00.00 [rcu_tasks_trace_kthread] Then, having the post-install reboot completed, and looking at top, I can observe the udev activities: top - 10:55:26 up 6 min, 1 user, load average: 2.16, 1.75, 0.84 Tasks: 108 total, 5 running, 103 sleeping, 0 stopped, 0 zombie %Cpu(s): 18.1 us, 22.7 sy, 0.0 ni, 48.8 id, 8.1 wa, 0.6 hi, 0.8 si, 0.9 st MiB Mem : 3988.9 total, 3274.2 free, 271.4 used, 539.0 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 3717.5 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1177 root 20 0 24884 5724 2560 R 33.2 0.1 1:50.24 (udev-worker) 1 root 20 0 168592 12912 8432 R 20.6 0.3 1:07.93 /sbin/init 690 root 20 0 467964 13112 10752 D 15.6 0.3 0:52.91 /usr/libexec/udisks2/udisksd 660 message+ 20 0 9328 4480 3840 S 14.6 0.1 0:52.68 @dbus-daemon --system --address=systemd: --nofork --nopidfile -+ 16285 ubuntu 20 0 18004 9984 8448 S 10.6 0.2 0:33.06 /lib/systemd/systemd --user 385 root 20 0 24764 7492 4676 S 9.3 0.2 0:30.40 /lib/systemd/systemd-udevd 373 root rt 0 288412 26368 8064 S 6.6 0.6 0:21.50 /sbin/multipathd -d -s 686 root 20 0 16096 7424 6528 S 4.0 0.2 0:13.20 /lib/systemd/systemd-logind 681 root 20 0 2066332 34480 21248 S 1.7 0.8 0:05.48 /usr/lib/snapd/snapd 14 root 20 0 0 0 0 S 0.7 0.0 0:01.90 [ksoftirqd/0] 20 root 20 0 0 0 0 S 0.7 0.0 0:01.87 [ksoftirqd/1] 25 root 20 0 0 0 0 S 0.7 0.0 0:01.27 [ksoftirqd/2] 333 root 19 -1 56736 23936 23040 S 0.7 0.6 0:03.42 /lib/systemd/systemd-journald 30 root 20 0 0 0 0 S 0.3 0.0 0:01.32 [ksoftirqd/3] 104 root 0 -20 0 0 0 I 0.3 0.0 0:00.55 [kworker/1:1H-kblockd] 138 root 0 -20 0 0 0 I 0.3 0.0 0:00.39 [kworker/2:1H-kblockd] 256 root 20 0 0 0 0 S 0.3 0.0 0:00.55 [jbd2/dasda1-8] Did the same (on the exact same system) with jammy 22.04.3 - nothing suspicious about udev, also not after post-inst reboot. On mantic I've noticed a flood of warning messages like: root@hwe0003:~# udisksctl monitor ** (udisksctl monitor:424911): WARNING **: 11:14:33.100: (udisksctl.c:2811):monitor_on_interface_proxy_properties_changed: runtime check failed: (g_strv_length ((gchar **) invalidated_properties) == 0) ^C (endless repeating messages) which I think fits to your observations, Dan. I've search for any already known udisks2 issue upstream, but couldn't find anything that fits ... Interestingly I get everything back to normal with just a 'systemd-udevd' restart: # systemctl restart systemd-udevd top - 12:16:45 up 20 min, 3 users, load average: 0.00, 0.33, 0.72 Tasks: 110 total, 1 running, 109 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st MiB Mem : 3988.9 total, 3260.3 free, 274.9 used, 549.6 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 3714.0 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 166794 root 20 0 11784 5248 3200 R 0.7 0.1 0:00.65 top 1 root 20 0 103052 13040 8560 S 0.0 0.3 1:49.42 systemd 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd 3 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_gp 4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_par_gp 5 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 slub_flushwq 6 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 netns 8 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/0:0H-events_highpri 9 root 20 0 0 0 0 I 0.0 0.0 0:00.39 kworker/0:1-rcu_par_gp 11 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 mm_percpu_wq 12 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_tasks_rude_kthread 13 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_tasks_trace_kthread 14 root 20 0 0 0 0 S 0.0 0.0 0:02.99 ksoftirqd/0 15 root 20 0 0 0 0 I 0.0 0.0 0:00.16 rcu_sched 16 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 17 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0 18 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1 After a reboot, I'm hitting the same situation again: top - 12:23:24 up 1 min, 1 user, load average: 2.48, 0.86, 0.31 Tasks: 138 total, 4 running, 134 sleeping, 0 stopped, 0 zombie %Cpu(s): 19.7 us, 24.1 sy, 0.0 ni, 47.8 id, 6.0 wa, 0.6 hi, 0.9 si, 1.0 st MiB Mem : 3988.9 total, 3527.3 free, 285.1 used, 268.7 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 3703.8 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 375 root 20 0 25096 5860 2816 R 33.6 0.1 0:30.19 (udev-worker) 1 root 20 0 101752 11760 8560 S 20.9 0.3 0:19.96 /sbin/init 591 root 20 0 467924 13060 10752 R 17.9 0.3 0:16.32 /usr/libexec/udisks2/udisksd 558 message+ 20 0 9316 4608 3840 S 16.9 0.1 0:15.39 @dbus-daemon --system --address=systemd: --nofork --nopid+ 12185 ubuntu 20 0 17996 9984 8448 S 12.3 0.2 0:07.06 /lib/systemd/systemd --user 373 root 20 0 24116 6784 4608 S 9.6 0.2 0:09.17 /lib/systemd/systemd-udevd 358 root rt 0 288412 26624 8192 S 6.6 0.7 0:06.34 /sbin/multipathd -d -s 589 root 20 0 16268 7424 6528 S 4.3 0.2 0:04.15 /lib/systemd/systemd-logind 585 root 20 0 1918612 31388 20352 S 2.0 0.8 0:01.89 /usr/lib/snapd/snapd 324 root 19 -1 40344 13880 13112 S 1.0 0.3 0:01.04 /lib/systemd/systemd-journald 14 root 20 0 0 0 0 S 0.7 0.0 0:00.45 [ksoftirqd/0] 20 root 20 0 0 0 0 S 0.3 0.0 0:00.43 [ksoftirqd/1] 25 root 20 0 0 0 0 S 0.3 0.0 0:00.47 [ksoftirqd/2] 30 root 20 0 0 0 0 S 0.3 0.0 0:00.43 [ksoftirqd/3] 36 root 20 0 0 0 0 I 0.3 0.0 0:00.10 [kworker/0:2-rcu_gp] 61 root 20 0 0 0 0 I 0.3 0.0 0:00.17 [kworker/u128:2-flush-94:0] 71 root 20 0 0 0 0 I 0.3 0.0 0:00.07 [kworker/3:1-events] Restart (or stop / start) of "systemd-udevd" helps again. I'm wondering now: - what is different during the installation that prevents udev from going crazy? (is systemd-udevd for example restarted during the installation at some point in time?) - and why is the initial start of systemd-udevd causing a different behavior than after it's its restart? (is there s/t missing when it's started at boot time?)