After a bunch of searching with some posts shedding some helpful insight they, however, did not completely solve my needs therefore I opted to post my specific conundrum.
I have a server with 4 bays summarised as follows:
1x 80gb Boot pool drive,
2x 1Tb forming the Data pool and
1x Empty bay
I currently have the 2x 1TB serving my data storage - I believe mirrored as on 1TB is usable. I purchased 2 more 3TB drives which I wish to use for the data pool and shares. The issue I am having is I essentially wish to replace the 1TB data pool with the 3TB drives and migrate the data across without loss.
The 2x 1TB drives are currently serving 3 shares which need to be preserved after the upgrade.
The part I am struggling to wrap my head around -mostly being completely new to Truenas, is I wish to migrate the stored data currently on the 1TB drives to the 3TB’s but also have the 3TB drives in RAID/mirrored.
I have poked around in the Pools settings but nothing seems to point me in the right direction on the interface to achieve what I am aiming for.
Any assistance in this regard will be greatly appreciated.