How to rotate external USB drive used for replication tasks

General Discussion
1

HI There,

I’m running TrueNAS Scale 25.04 with a document/photo archive accessible via Nextcloud for me and my family. Regular snapshots of individual datasets, and those snapshots are replicated to an External USB drive (single HDD).

I want to start rotating this USB drive with a second (and similar) HDD to allow offsite storage of said drive. However, I’m unsure how to arrange the mounting of both drives (alternating) without messing up the replication tasks.

Will both drives be part of the same pool? and thus act as the same dataset with Truenas not knowing the difference? Do I need to shutdown Truenas before swapping the drive, or can USB be considered hotswappable?

2

Each HDD will be a single drive pool, and you export this pool, from GUI, when you’re done, and unplug. (Do not tick to destroy the pool on export, of course.)
I suspect that if both drives have the same pool name you can use the same replication task for both and ZFS will work out the latest common snapshot between source and destination. At worst, you’d have one task for replication to “external1” and another for replication to “external2”.

3

So it is the export function (and import i guess?) I need to use, similar to “eject” in windows or Linuxmint?

Sounds easy enough on its own, will give it a try.