Many thanks. My LVM system now starts successfully, albeit still showing the 60s hang occasionally. Even the supposed-to-be-affected logical volume is mounted correctly. Just the "/sbin/lvm vgchange -a y" persists in the process list, but this apparently does not harm.
One additional note I want to make: I'd set the udevadm-control timeout at least to 70 seconds. The epoll_wait timeout is reset every time something happens. So if the "settle time" is bigger than 1 second, the total timeout would be more than 61 seconds of udevadm-control. Setting the timeout to 70 seconds, gives us at least 10 seconds "settle time".
My conclusion is that "udevadm control --exit" (introduced in april) is still a bit immature, and further races might wait to happen.
Many thanks. My LVM system now starts successfully, albeit still showing the 60s hang occasionally. Even the supposed- to-be-affected logical volume is mounted correctly. Just the "/sbin/lvm vgchange -a y" persists in the process list, but this apparently does not harm.
One additional note I want to make: I'd set the udevadm-control timeout at least to 70 seconds. The epoll_wait timeout is reset every time something happens. So if the "settle time" is bigger than 1 second, the total timeout would be more than 61 seconds of udevadm-control. Setting the timeout to 70 seconds, gives us at least 10 seconds "settle time".
My conclusion is that "udevadm control --exit" (introduced in april) is still a bit immature, and further races might wait to happen.