Hey David,
So the easy thing to do is to split your collection from a single 12tb drive to between disks. Of that 12tb, how much was shot in the last year or two?
By moving 6-8TB of old data off the constantly access 'active' drive to a 'archive' designated drive, you accomplish a few things:
- Free up space on your 'active' drive
- Shorten your backup/sync time (since it's only backing up the active drive)
- Create static, point in time reference for the 'archive' drive (example of 1990-2006 or such) that can be duplicated
Say you went to Costco & grabbed 3 of the $120 8tb drives. I'd fill one up with a good 'archive' set of ~7TB of data, then SuperDuper that drive twice, one for a local offline copy, and a 3rd for the offsite backup copy. Then just keep doing what you're doing with the current 12TB Lacie drives, just with that now 'archived' data on a separate disk.
If you needed to work on something from the archive set, create a root folder on the 12TB Lacie and copy it over from the archive drive & work on it there.
Don't over complicate things, especially since management of the data can become a larger hassle. Lightroom is fine with it - just right click the 'missing' folder and update its' location on the archive drive.
-Joe