[Borgbackup] suggestion append data for existing archive

[Marian Beermann]

Hi Judith,

On 28.08.2017 17:18, Judith Brown wrote:
> If am searching for a backup + optimal solution to raspberrypi media management.
> Assume I have a (2TB) large /media/SOURCE and small /home/pi (~8GB from microSDcard).
> I do a first backup:
> borg init /media/2TB_BACKUP
> borg create  /media/2TB_BACKUP::archive-1  /media/SOURCE
> 
> Now, I mount
> borg mount  /media/2TB_BACKUP::archive-1  /media/DATA
> 
> I remove 2TB /media/SOURCE
> Now I mount a small 8GB usb stick at /media/SOURCE
> 
> My suggestions:
> 1. If I run (with 8GB usb stick)
> borg create  /media/2TB_BACKUP::archive-2  /media/SOURCE
> this archive will have only the NEW 8GB data. 

Yes

> 2. Can I access *all* data from archive-1 + archive-2 at the sametime at the same mountpoint?

You can mount the entire repository (just leave out the "::archive"
bit). Each archive is then a directory under the mountpoint.

(Because archives are loaded lazily this doesn't consume many resources
for many archives at first).

> Instead of (1), it would be great if there was a 'append' parameter,
> so that I can 'append' data onto the archive-1 thereby while
> 'creating+adding new data borg does compression+dedup. This after
> initial setup I can make /media/2TB_BACKUP and make it my main
> 'disk' since it features deduplication and compression! (onto any
> filesystem - like ext4 or XFS).

An "append-to-archive" operation has been brought up before but
is usually not considered to be in the spirit of Borg. See e.g.
https://github.com/borgbackup/borg/issues/2143
https://github.com/borgbackup/borg/issues/1935

I also once had the idea to use Borg for media archival / management as
well (strong checksumming, dedup), but it's not really practical with
the current features and the necessary extensions to enable this use
were not considered a good fit by project members. See
https://github.com/borgbackup/borg/issues/2263

I settled on ZFS (zfs on linux), btw.

Cheers, Marian