[gentoo-user] systemd boot timer

[antlists]

I'm trying to get a systemd unit to fire on boot once a week. Reading up 
on timer units, I can't work out how to get it to work.

This is tied up with my earlier systemd mount post - I've now got that 
sorted - I've got dm-integrity to fire before fstab.

I now want to run lvm snapshot on the first boot of the weekend. Writing 
a unit to do the snapshot seems pretty easy, but obviously I don't want 
it firing every boot, if I stick the date in the volume name I don't 
want it colliding with an earlier run the same day, etc etc.

The question really is - if I have a weekly timer fire and activate the 
unit, is the activation going to survive the reboot to run on the next boot?

The problem I'm having is that all the stuff I've seen about timers says 
you have two lines - activate on Saturdays, and activate on boot. Snag 
is, they seem to be independent such that EITHER condition will activate 
the service. As I say, I want BOTH. I don't want the service running 
while the system is up and running.

Cheers,
Wol