Deduplication should work the same with hot and cold storage thanks to Duplicati’s local database with no effect on versioning.
However, retention policy cleanup will likely queue up until a compact is run (either manually or through re-enabling auto-compact).
Other than that backups should run as expected with the following caveats:
- there is no longer any listing / testing of your remote files to make sure they haven’t disappeared or gotten corrupted
- there is no longer any automated retention policy cleanup / compacting
- any testing, compacting, or restores will need to be preceded by a manual request to your provider for ALL cold storage files to be moved back into hot storage. Note that if you have more files in cold storage than space available in hot storage then this could cause a problem…
This topic (or searching the forum for “cold”) might provide some more background (and maybe a few people to ping to see how it worked for them):