Am 13.02.2014 00:14 schrieb "Kai Krakow" <<a href="mailto:hurikhan77@gmail.com">hurikhan77@gmail.com</a>>: > > Mirco Tischler <<a href="mailto:mircotischler@gmx.net">mircotischler@gmx.net</a>> schrieb: > > > It's late here so excuse me if I'm missing something. But wouldn't a > > simple Before=sleep.target suffice to implement b)? > > I'm not sure... The unit is not enabled, only triggered by the timer - so it > may work. I think I may try that as an alternative to systemd-inhibit. > Systemd-inhibit just does not feel like the right tool for this. > > > If your backup job is still running it blocks sleep.target's start until > > it finishes. > > Then, what happens if I start using my system during backup, sleep.target > had been triggered but is waiting for the backup job to finish? Will it > simply go to sleep then while I am using the system? OTOH, will systemd- > inhibit cover that case? > Yeah, the job to start sleep.target will still be active, so this should only work for overnight stuff. > Twisted around: What happens if sleep is triggered by the system due to idle > time while sleep is inhibited? Will it trigger as soon as the inhibit is > removed again? Or will the idle timer for my system just trigger sleep again > after it has passed a second time? > Systemd-inhibit has the options block and delay for this. But when and if the idle time gets restarted is up to the idle timer ;-) > > Though for the grace period some ugly hack such as > > "ExecStartPost=/usr/bin/sleep <n>" would be required. > > My primary concern here is btrfs doing a lot of background work when > handling snapshots. My backup medium is a btrfs with rsync copying the > source as in-place deltas to a scratch area, then taking a snapshot of it. > Later, I'd like to automatically cleanup old snapshots - but that means I > should wait before going back to sleep until btrfs finished that job. A > simple "sleep" probably won't do. I suppose it would require an option like > "--wait" to "btrfs subvolume delete", then wait another 5 minutes to give > all pending write commits a chance to make it to disk. Sounds like you want systemd-inhibit for both your backup service and the btrfs subvolume delete 'service'. And the kernel will call sync() before suspending, shouldn't that suffice? > > -- > Replies to list only preferred.