You rolled back the primary dataset? Was the rollback so far into the past that its latest snapshot had already been pruned on the backup dataset?
What did you need to troubleshoot on the primary that couldn’t be done without a rollback?
Two options.
- You can “clone” from a snapshot into a new temporary dataset that you can point Plex to.
- You can retrieve individual files and folders from a snapshot without the need to rollback anything.
These are alternatives that don’t require rolling back.
There are also ZFS bookmarks, which can get you out of these situations (sometimes), but it’s not exposed in the GUI, unfortunately.