Switching two external drives once a montn

General Topics
1

Hey there,

I have a Windows11 desktop computer which I want to backup. I will use KopiaUI for doing this.

What I want:

  • daily backups of some directories
  • backups being done automatically in the background
  • switching between two external harddrives as backup-destination

What I mean is, that I have two external drives. One is connected to the PC and the other one is stored externally. Once a month I’ll switch those, so that one backup is stores outside the house with backups not older than a month.

How should I achieve this? Should I just add two repositories, one for each drive? Meaning, that one will always be seaching for its storage, or is there some besser way?

Thanks a lot!

2

The repository resides only on the external HD, only congif information is kept locally. So, yes you would need to create a repository on each HD once. On the PC, when rotating HDs, you disconnect the repository, then connect to the repository in the othe HD. You can name the repository the same on both HDs (after all this is nothing but a directory on the HD).

Note also that Kopia offers repository synching kind of to achieve what you want. You backup (snapsot) to HD1, then regularly attach HD" and do:

kopia repository sync-to filesystem --path=path-to-repository-on-HD2

This will copy all new blobs from repository on HD1 to HD2

It will not delete any blobs on HD2, which have been deleted on HD1, due to kopia’s maintenance. If you want those to be deleted on HD2, too, add the delete options:

kopia repository sync-to filesystem --path=path-to-repository-on-HD2 --delete

Note that I have just donoe something similar, but wanted to rotate the HDs as you propose, so do snapshots to HD1 for a while and synch from HD1 to HD2, then rotate, i.e. snapshot to HD2 and synch from HD2 to HD1. This does not work. See Problem rotating external HD with “repository sync-to” on this forum.

Synching has the some disadvantages, though, over only rotating and snapshotting:

  1. If some file gets somehow corrupted, then snapshoted on HD1, the synch would copy the corrupte file’s blob over to HD2. If you simply rotate, there is the change of odentifying the problem and having a valid blob on the other HD.
  2. You need to connect both backup disk in parallel, so expose both backup copies to the remote possibility of some “damage”. If you simply rotate, you alway have a working copy, no matter what happens to the one attached to the PC.

Due the problem I have stumbled accross with rotating and synching (see above link), I’m thinking of going the rotate only way as you describe. Will have to do some tesing with this.

3

Thanks a lot for your reply!

Then I’ll do it with two repos which are switched. Syncing is no opportunity to me, as one disk is always stored 100km away, at my parents house. So I’ll take the current local disk, drive to my parents, interchange the disks and connect the other one at home. To do the sync, I’d have to drive two times, to bring both to me at first. And the disadvantages you say are good reasons to avoid it, too.

So, thanks again :slight_smile:

P.S. But do I have to disconnect the repository, which is currently not connected, or can I just let it active (not finding the storage). So I’d have always two repositorys activated, but only one which can find it’s storage. So the only thing to to is switch the drives, but not handle the repos in kopia.

4

P.S. But do I have to disconnect the repository, which is currently not connected, or can I just let it active (not finding the storage). So I’d have always two repositorys activated, but only one which can find it’s storage. So the only thing to to is switch the drives, but not handle the repos in kopia.

If you’re using the GUI (KopiaUI), then there is no need to disconnect. the GUI remembers all the repositories once connected. In the GUI popup, you’ll see the one for which it finds the HD listed with the repo’s name, the other will be listed as “initializing”.

At least this is the behaviour I see with my two HDs mapped to different Windows drive letters (assigning drive letters with the disk management utility of Windows).

I don’t know if there is any disadvantage of having multiple repositories in the connected state in parallel.

If you’re using the CLI, then you would need to disconnect and reconnect, I think.

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