[Duplicity-talk] Mirroring then writing to multiple backup destinations?

[Rubin Abdi]

The short question: Does Duplicity keep any sort of backup knowledge
data not in the actual backup destination? Or does Duplicity figure out
the state of the backup destination by looking at the actual destination
each time?

Setup:
 * Laptop with important data
 * Home server with other important data inside of a large RAID6
 * Backup-A USB drive, plugged into server
 * Backup-B USB drive, kept offsite most of the time

When at home I would like to periodically backup my laptop to Backup-A
plugged into my home server, most likely when I'm about to go to sleep
and remember to plug my laptop into the wired local network, multiple
times a week. On my server I want a cronjob to also periodically backup
important data from the RAID into Backup-A.

I live in a disastrous city called San Francisco, where there's a high
chance that tomorrow an earthquake will happen and swallow my flat into
the ground or some unwelcome party going friend of a friend hipster may
inadvertently spill cheap beer all over my server. And so I have
Backup-B which I typically keep offsite across the bay, unplugged from
any networks.

Once a month I would like to bring Backup-B back to my house and
basically mirror all of Backup-A to it, completely so they're 1:1,
backups for both laptop and server RAID. After that mirror/update is
done I will go and take Backup-B back to its remote site across the vast
distance that is the bay.

Two or three times a month I might find myself at the remote location
where Backup-B is being stored along with my laptop and would like to
update the laptop's portion of the backup. There is a good chance that
between the time I last mirrored Backup-A to Backup-B, and now doing
this offsite laptop to Backup-B, I've already made multiple backups to
Backup-A.

So my longer question would be can Duplicity possibly get confused if I
attempt a backup to a destination that has a state older than the
previously destination it might have used the day before?

Thanks!

-- 
Rubin
address@hidden

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