borg2: confused about tags and timestamps

[tve]

I'm a bit confused about the tags (in the general sense) that are applied to an archive. For one, it would be great if -v listed what borgs records, e.g, hostname, user, timestamp, comment, tags.

When I pass --timestamp /some/directory I was expecting that borg would record the ctime of that dir as timestamp for the archive. But I don't see anything like that when running borg info. Also, borg info doesn't really list a timestamp but "Time (start)" and "Time (end)".

I also see option to match archives by tags but I see no way to specify tags in borg create. What am I missing?

[ThomasWaldmann]

Guess create does not have tagging built in. Also, maybe we rather want to avoid that, borg create is already very complex and has a ton of options.

Maybe we can rather change borg tag to make it easier tagging the archive that was just created by borg create. Could just tag the most recent archive of a given series name.

[tve]

I see... Had forgotten borg tag...

[ThomasWaldmann]

About borg create --timestamp: iirc, it should set the "start" timestamp.

When you give a file, the docs just say that it uses that file's timestamp, but it does not say which one. :-)

[tve]

It does not seem to use the timestamp that ls -l` displays...

[tve]

Add-on question: is there a way to specify the hostname? The use-case I have is that I run borg in a container and (at least using podman) the hostname in the container is something random. I can fix that by passing a --hostname option to podman but it would be cleaner to do that explicitly to borg since one has to pass the hostname explicitly when matching repositories.

Another use-case would be backing up a remotely mounted filesystem which one wants to associate with the remote system's hostname.

[ThomasWaldmann]

There is no option yet to overrride the hostname.

It would be good to file a separate ticket for each issue.

[ThomasWaldmann]

Giving a file (or directory) for the timestamp works for me (and it uses its mtime).

(borg-env) tw@MacBook-Pro borg % borg create --timestamp pyproject.toml arch docs

(borg-env) tw@MacBook-Pro borg % borg repo-list                                  
b5956440  Thu, 2026-02-19 22:21:25 +0100  arch                         tw          MacBook-Pro  

(borg-env) tw@MacBook-Pro borg % ls -l pyproject.toml 
-rw-r--r--  1 tw  staff  9295 Feb 19 22:21 pyproject.toml

(borg-env) tw@MacBook-Pro borg % borg info aid:b5956440
Archive name: arch
...
Time (start): Thu, 2026-02-19 22:21:25 +0100
Time (end): Thu, 2026-02-19 22:21:25 +0100
Duration: 0.042 seconds
...