I’m no expert on this, but it seems to me that the argument makes more sebse the other way around: a one-per-month policy would be followed by keeping a snapshot from the 31st and one from the 1st of the next month whereas the 30 day policy makes sure that they’re 30 days apart, no?
Looking at Removing backup snapshots — restic 0.9.2 documentation, I don’t see much difference to duplicacy (rather, it looks like the duplicacy I notice that it says " prune
options have been inspired by the restic forget
options).--keep-daily n
for the last n
days" instead of just “keep one for every m for the last n days” as in duplicacy. Is that what you mean? I agree that this would be better. Edit: no wait, isn’t the duplicacy way of doing it more flexible because it’s more generic? In that case, maybe introducing the restic options as aliases would help?
I notice one important detail in the restic documentation, though: they specify that it is always the last snapshot that is kept, for example:
--keep-weekly n
for the lastn
weeks which have one or more snapshots, only keep the last one for that week.
I’d assume that this is the case with duplicacy too (@gchen?) and if that is the case, we should make it explicit in the documentation.
This is also something that you can do in restic but not in duplicacy. In duplicacy you can just keep 24 in the last day and if you made hourly backups, these will we the ones kept.