I seem to get intermittent systemd time out errors when trying to mount btrfs, which throws the system into systemd rescue mode.

e.g. "Job dev-sdb1.device/start timed out."

I can't actually see any reason for the problems in the systemd journal.

Furthermore, "mount -a" from rescue mode works perfectly.

Maybe the hard disks just aren't "waking up" fast enough in the boot sequence. I have reported slowness here before when system is cold, which I suspect is hard disk related (spinning WD disks). Hmm. It is now booting fine again, maybe I need to leave the hard disks on for a while before they start working properly...

smartctl reports nothing abnormal.

Any ideas?

Maybe time to get new hard disks?

Thanks