Re: n00b questions about using dar for archiving wikis [apologies]

On 23/07/2021 08:43, griffin tucker wrote:
> i didn't mean to upset you, i don't want you to do any development
> unnecessarily.

no worries, I just had not time to answer you, having a quite busy week
at work, sorry for that.

In brief, if you want to add new files to an already existing and
completed backup, you cannot do that with dar (you can with tar but have
to disable several other features, like compression and multi-volume
AFAIR). With dar, you rather make a differential backup, or another full
backup and convert the previous full backup to a decremental one.

There is no plan to have such feature with dar as it would ruin the rule
followed by dar to never modify an existing backup, but create a new one
beside the old ones (while repairing, merging, and other operations)
leaving the decision to the user to remove *or not* the old backup
keeping them, for example, as secondary backups.

As explained in a previous email, the binary delta feature (that makes a
rsync like increment) is not available with decremental backup today.
Without this feature, when a file's data changes the whole file is saved
again (and is eventually compressed in the backup depending on your
choice). Technically having binary delta with decremental could be
possible, but so far the need did not seemed very strong for that.


If you don't know whether dar is the tool that matches you need, check
the documentation like the tutorial, it's always better to validate by
yourself as you know better than anyone here the goal you tend to address.

tutorial: http://dar.linux.free.fr/doc/Tutorial.html

Feel free to ask if you have any particular question on how works or how
to use any particular dar/libdar feature.

Cheers,
Denis