You may mean 3 TB hard drives?
You need to EXPORT your Sooloos library in NATIVE (FLAC) format to the drive you will be using for Roon.
Export and Back up are different. The export will take some time depending on the size of you library.
Then point Roon at the new library and your good to go.

Chris smile

No 18 in the Hall of fame smile I have simple tastes; I am content to settle for the best:
GIK monster bass panels, rear wall. QNAP TVS 471i3. Roon into DSP5200SE via 210/ 218 zone... Explorer 2. Bluesound Pulse 2, Mini & Flex. 596v1, 518, Foxsat HD, Sony BDP, Pioneer 5090, 2 Chromecast's for LRB videos. MS200 to F80 for a Roon zone