Per-repo default parameters (chunker, compression)

[level323]

I think usability of borg could be improved by being able to set default values for certain options at repo initialisation time.

For example: borg init --chunker-params-default 18,23,21,4096 -compression-default lz4 my-vm-image-repo

Per the above example, any subsequent borg create invocation would use the chunker params and compression defaults specified above, but could be overridden by explicitly specifying the standard --chunker-params and/or -C arguments following borg create

Creating per-repo defaults for chunker params and compression would scratch my immediate itch, but on further thought there are many other post-init invocation arguments for which per-repo defaults may improve usability, such as umask. no-files-cache, etc.

The most obvious ways to implement this feature would be either:

1. Along the lines of my example above - that is, a slew of --XXXXX-default optional arguments to the borg init command.
2. A new borg command such as borg repo-set-defaults --chunker-params 18,23,21,4096 --compression lz4 etc that could be invoked (if desired) after borg init

Cheers

[theamk]

One way to solve this is to extend the capabilities of the /config file in the remote repository. It already has segments_per_dir and max_segment_size ; other per-repository parameters like chunker-params, compression, and umask seem like a natural fit there.

This will eventually require command line options to edit as described in the bug, but for the first version the user can just edit the file.

[ThomasWaldmann]

note that umask must be set rather early, so that it is in effect before any files/dirs get created.

[leegarrett]

(Sorry to grave dig this bug)
+1 to this.

My current line for making backups is:

BORG_CACHE_DIR=/mnt/target/borg_cache_batou /usr/bin/borg create --progress --stats --exclude-from /home/randall/Coding/randallscripts/borg_exclude_patterns --exclude-caches --noatime --nobsdflags --noxattrs /mnt/target/batou::batou_$(date -Iminute) .

That's impossible to memorize, and currently any command (e.g. recreate) involves copy/pasting that around, which is not very practical.

It would be a great feature to be able to set it per-repo in ./config, or per-user in ~/.config/borg/.

[infectormp]

Also, you can put all these args to env and call it from script

[ThomasWaldmann]

There will be a default config per user after #9413 is merged.