My experience with attic (seems to be a trend with all of your dedup reviewed systems) is that it also takes a very long time to restore large amounts of data _however_ you have the option of restoring individual files via a FUSE file system which is _immensely_ useful.

An example was that a restore of ~200 GiB of VM snapshots took over a day from a NAS to the server in question.

Usually, the backups take about an hour to write out, so reading data from attic does take significantly longer.

This is probably because dedup is non-trivial to restore from (it can involve lots of random reads/disk seeks).