Backing up multiple paths at once

Getting Help
1

I made an initial backup of multiple paths of my NAS, about 600 GB. Reading from the NAS was the bottleneck. To simplify, I backed up n:\a, n:\b and n:\c (I’m on Windows). After about 2 hours or so the backup was done and I realized I also needed n:\d, so I backed that up as well.

Then, to be complete, I wanted to make a snapshot of all 4 paths, so I started one last backup on all folders at the same time. To my surprise, Restic started to read everything again, so the final snapshot is going to take another 2 hours. Why does it do that? It already has all the information it needs. I think this is a very big disadvantage of combining multiple paths in a single snapshot when datasets are relatively large.

2

Wouldn’t then be more logical to run restic directly from NAS? It runs on pretty much anything.

3

I was backing up to an external drive that was connected to my PC, running the backup from the NAS was not practical in this case.

Anyway, the backup is finished. Incremental backups will be very fast from now on. I just have to make sure I don’t add another path to the backup.

4

Still interesting why it had to read all folders again. I agree that it does not seem logical.

5

Assuming the paths to backup are identical across the snapshots, as they appear to be in your case, I believe specifying the previous two snapshots as parents would have helped with the initial speed of the third “combined path” snapshot:

https://restic.readthedocs.io/en/stable/manual_rest.html?highlight=parent#usage-help

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6

Wow, that is a cool feature. I did a cool test with that. First backup n:\big, then n:\small, then n:\big + n:\small with big as the parent and it only had to read n:\small again.

Thanks for the help! Now I don’t have to worry about adding paths to a backup.

7

Note that currently only one snapshot can be specified as parent unless backup: Support multiple parents by aawsome · Pull Request #3121 · restic/restic · GitHub is added to restic. Note that that PR would also have automatically found the necessary parents.

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