Thanks to Helmut, that plan sounds really good to me!
A few little details to add (but they do not influence the suggested
upgrade procedure):
One actually has to create NEW repos for borg2 and then has the options:
- to just have the future backup archives in these new repos, or
- to "borg2 transfer" existing archives from the borg1 repos to the
borg2 repos and afterwards add future backups
The transfer might take quite a while, depending on the archive count
and the amount of data. It does deduplicate, so the transfer of the
first archive usually will take a long time, but subsequent similar
archives will transfer faster. The src and dst repos will be locked, so
they can not be used for anything else while the transfer is running.
If one wants to transfer old archives, one needs to create **related**
borg2 repos ("related" means some of the secret key material from the
old borg key is copied to the new key, specifically the chunker secret
and the ID-hash key). This makes sure that past backups will deduplicate
with future backups.
borg transfer in a client/server setup (ssh:// repos) will need a borg2
on client **and** on server.
