[systemd-devel] How to prevent sleep during running oneshot units
hurikhan77 at gmail.com
Tue Feb 11 16:30:59 PST 2014
I've got a daily backup job scheduled using a timer unit and a oneshot
service file. This backup takes around 2-4 hours. It's using rsync and syncs
from btrfs HDD to a snapshotted btrfs on USB with inplace deltas. I'm
mentioning this because it may matter.
I've also set my system to auto-sleep after 4 hours of idle time. This
means, in KDE I've set the option to put the system to sleep after that time
This usually works fine. But sometimes during backup, the system cannot
sleep. I see it still powered fully on the next morning. In dmesg, a lot of
btrfs and blockdev related tracebacks accumulated with notes of being unable
to sleep because a processed has refused to stop. I don't know if this is
btrfs-related or not - but actually I don't think it's wise to go to sleep
while the backup process is still running either.
There may be a bug here, because almost every time when that happened it
looks like systemd has suspended my network connection but didn't bring it
back online after the system refused to go to sleep. I need to restart
NetworkManager then or reboot (I prefer reboot to alleviate any other side
effects that may have had).
But what actually results from this is the following question: How do I
prevent systemd from trying to go to sleep while the backup job is running?
I'd like it to either (a) do not go to sleep at all (do not even try) or (b)
defer the sleeping signal until the backup job finished, with (b) preferred
plus some grace time.
I don't know if something like "Conflicts=sleep.target" would do the job, I
even do not know if that would be a good idea at all.
Ah, and then another one, more or less unrelated: Lennart one time told me
that it's on the feature plan for systemd to wake the system up for selected
timer units and put it back to sleep afterwards. It would be a nice-to-have.
Still on the feature list? Maybe any news on that? I'd like to test it.
Another one, partially unrelated: I've set up the backup mount point with
automount in systemd (via fstab). Is it possible to automatically undo that
automount upon finishing the backup job? If I explicitly call umount, the
job could wait forever if I accidently left a shell open in that directory.
This more or less concludes to the question: Could automount units also
automatically unmount after some idle time (after nothing any longer
accessed the volume)?
Replies to list only preferred.
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