Big Sur, sleep, slow

My machine (mac mini m1) is scheduled to start backup at 00:01, it starts but runs very very slow. When I start working at 08:00 the machine has not finished backup, check, prune. I guess it’s because it’s in some semi awake state and runs very slow. Is there a good fix for this behaviour?

The easiest would be to prevent Mac from sleeping in the system preferences: Likely what happens is your Mac does wake up occasionally (see Dark Wake) to do some maintenance but then goes back to sleep shortly after, not giving duplicacy enough time to finish the backup. You can confrim whether this is what is happening by looking at pmset -g log.

if you are running command line duplicacy you may consider running it under caffeinate -s to prevent system sleep for the duration of the backup; for the web version you can do the same using pre- and post- backup scripts. see man caffeinate

Yes Dark Wake happening. Will look into caffeinate, I’m running web version, so will need to do the pre/post scripts.


Hi again, after reading up about caffeinate, I fail to understand how it would be possible to use it in a pre-script. I have to run caffeinate without a utility otherwise it will exit directly and remove the assertion.

So you mean that I shall run caffeinate in the pre-script, and then kill it in the post-script? There is no way of managing these pre/post scripts from the web either, which is a bummer.

Yep, that would be the way.

I would also submit feature request to ask to have a flag added to duplicacy CLI to set the assertion to prevent sleep for the duration of the backup.