Inconsistent weekly retentions

[8191]

I’m trying to make sense of the retention labels. Can someone explain why the backup of Jan. 4th has no weekly-3 label?

[kapitainsky]

There is no better snapshots retention logic explanation than this post:

Kopia Snapshot Retention Policies Demystified

With the suggestion of @JayKay729, I decided to create a dummy backup for testing how Kopia choose which backups to save, but in this experiment, I learned much more than I initially planned. In this post, I would like to share these discoveries, along with some examples to demonstrate them. This is a supplement to his post, so I’ll jump straight to those he hasn’t covered yet. Numbers in Snapshot Retention [image] Except for Latest Snapshots, Kopia considers the number you write here as dura…

[ingul-buz]

The problem here is that the logic fails: there’s one week left completely without a weekly tag.

• 12/27/2025 snapshot falls on week 52
• 1/11/2026 snapshot falls on week 2
• 1/13/2026 snapshot falls on week 3

So, where is the weekly tag for week 1? 1/4/2026 snapshot falls on that week, but didn’t get a weekly tag assigned. I noticed the same inconsistency with my own backups.

[kapitainsky]

@ingul-buz

The problem here is that the logic fails:

We do not know really what the logic is here:) In the linked thread somebody tried to reverse engineer it as kopia docs are missing such details unfortunately.

@8191 What time zone you are on? Are you using kopia server? If yes is it in the same timezone?