Ok, so an update (also in the hopes of getting some replies here): My Drobo's 6Tb drive got ejected from the array, but still being under warranty, I took it to the store I purchased it from. They ran it through a thorough test and it came out clean, so perhaps the Drobo had a glitch.
Anyway, in the meantime I got an 8Tb replacement drive. I ran it through a vigorous badblocks test which took about a week. When it passed that, I plugged it into the unRaid box as a single device share, and I have been using rsync to copy over all 6Tb of data from the Drobo to the unRaid share.
When that's done, I guess I'll be installing a Plex docker container, but that's where I need help. I don't want to lose any Plex watch history, so all that needs to come over from the Drobo. However, I also need to somehow make sure the paths are correct, and I don't know how to do that.
Finally, I'd appreciate some advice on how to handle my data all being on one drive:
Do I plug in all the other drives from the Drobo, set them up as a separate share with drive redundancy (parity?) and whatnot, and then copy the data from the 8Tb to the multi-drive share to get it to be stored with parity/redundancy?
Or can I just add the drives from the Drobo to the existing single-drive share? My understanding is that the largest drive(s) should be the parity drive(s), but the largest drive would have all the data stored on it, so how do I go about it? If I mark a drive that has data on it as a parity drive, will unRaid intelligently and transparently transfer data from that drive to the other drives in the share?