TerraMaster Official Forum

Hey guys, as I have to move my files off another RAID system ASAP and only plan on getting a T6-423 next month (because money), I'm thinking of getting two 16TB drives to copy my old RAID onto and then add these plus a third 16TB to the T6-423 to create a new RAID5.

Is it possible to create a RAID with two already filled drives without losing my data?

No, if you move your RIAD to T6, your drives need to be reformated, you can't keep its data.
Compare to RAID 5, TRAID is better for future capacity expansion.