Consider adding an option to skip the backup entirely when there are no new or changed files

[x80486]

This will save time and resources, especially for backup locations that don't change frequently.

Borg could detect that nothing has changed since the last run, and skip creating the subsequent one.

[ThomasWaldmann]

I don't think that this will "save time and resources":

• to determine whether anything has changed, borg create would need to do the same effort (and take the same time) as it does for creating a backup archive: iterate over all files and directories
• because borg deduplicates, a "no change" archive takes only a few bytes storage space (for the archive metadata)

[x80486]

I wanted to start this thread for the same reason — if nothing was added and/or changed, there is really no meaningful reason to create a new (no-change or empty) snapshot.

This could be under an option, and it's probably wise to maintain the default behavior, because there will be somebody somewhere that will still want the no-change snapshot.

[PhrozenByte]

One thing to add: This is also not ideal when considering retention policies.

There isn't really any reason to treat empty archives differently.

However, if you really want to do this, you can easily implement it yourself: Have your backup script run borg diff to compare the last two archives, with or without --content-only, and check the output. borg diff produces no output if the archives are identical; otherwise, you can use --json to process the results programmatically. If no changes are detected, delete the newer archive using borg delete.

[ThomasWaldmann]

Note: "empty" rather means "identical" here in this context.

It's not empty, it contains the same metadata and references as the previous archive(s). It just does not consume significant space because everything is deduplicated.

[x80486]

I will leave the decision up to you, since you seem to be leading the development (I reviewed the commit history) on this project — along with Claude 😉

I think the suggestion itself is clear at this point, and if you think it would be useful to offer this as an option, I'm sure that some people would find it very convenient.

And while there may be some other ways to reach out to a similar result, my point is less about what users can do themselves and more about what the tool could provide.