Revisions and Pruning - Gui Help

[craig1]

Hi guys,

So I’m using Duplicacy from my unRAID box, with multiple storage locations for each backup to keep it nice and neat (and to take full advantage of each users’ 1TB of OneDrive storage space). I have a couple of VERY n00b questions.

I’ve setup the backups, and throttled them. However, by default are these differential backups? If so, how many revisions will be backed up before “rolling over” and starting again?

Once I’m happy with the backup process and it’s all going well, is Prune the command that people use to keep those revisions/generations of backups under control? If so, what is a standard command that most people use? Some of my backups are going to change infrequently so I really don’t need too many revisions given I’m only backing up, weekly.

The pruning bit, especially, doesn’t quite sink in. I’m used to the terminology of ‘generations’ and ‘retention periods’. Is this the same.

Any n00b help that can be given, I’ll send virtual positive vibes your way

[saspus]

@craig1

However, by default are these differential backups?

Yes, and no. Only deduplicated difference will be uploaded on each backup run – so in this sense they are differential and incremental, but each backup behaves like an independent full backup: you can delete all previous backups and it will work just fine

@craig1

If so, how many revisions will be backed up before “rolling over” and starting again?

∞. Please clarify what “starting again” means in this context.

@craig1

Prune the command that people use to keep those revisions/generations of backups under control?

Depends. The default that DuplicacyWeb creates when you add prune job is reasonable enough.

@craig1

I’m used to the terminology of ‘generations’ and ‘retention periods’. Is this the same.

Yes. Duplicacy’s -keep command controls what to keep – e.g. -keep 30:14 applies to backup snapshots older than 14 days and keeps one version every 30 days. They are combinable – from oldest to youngest:

duplicacy prune -keep 0:360 -keep 30:180 -keep 7:30

This means: only keep one version per week after 30 days, one version per month after 6 month and no version older than a year.

You can implement GFS with this easily, or more complex something. I tend to match what Time Machine in macOS defaults to: -keep 7:30 -keep 1:1 and backup hourly.