Change pack size on existing repository

[kapitainsky]

Here is the answer:

Snapshot copy and corrupted data recovery

It’s possible to repack too small pack files using restic prune --repack-small --pack-size size. Using copy to move all data to a new repository is also possible, as copy transfers the data blobs contained in pack files, but not the pack files themselves. This leads to the construction of new packs, with the specified pack size. See https://github.com/restic/restic/pull/3731#issuecomment-1207189014 . It’s somewhat randomly chosen, increasing the maximum further should be possible, but will req…