by FadingIntoBlue » Tue May 29, 2018 2:59 pm
I think you have a few more factors to consider than just the Filevault encryption and the core storage issue. I have found difficulty in moving disks from one enclosure to another, primarily with USB, but on occasion with Thunderbolt. I suspect it is something to do with some combination of bridge hardware, disks, disk order and how the enclosure presents to ZFS, if that makes any sense. I haven't used eSATA so not sure if there is an issue there. The approach I'd take is:
2: Back up your existing data (you already have a backup or two right? ZFS is not a backup strategy by itself)
2: Split both your existing mirrors, leaving you with two copies of all your data
3: Take 1 disk from each split mirror, and install in the FreeNAS box
4: Create a zpool by adding the 2 disks together - no redundancy at this stage
5: Copy your data from the existing pool to the new pool (zfs send, rsync, finder or whatever)
6: Once you have a successful copy, take the disks from the old pool, and use them to mirror the disks in the FreeNAS box
That might be a bit of a long winded approach, but it avoids the underlying encryption and disk format issues. You never have less than 2 copies of your data, so it is reasonably safe from that point of view too. Of course buying a new set of disks for the FreeNAS box is a lot simpler, but not nearly as frugal.