What I have now:
5-drive RAID 5 array connected by Thunderbolt, using 2TB drives, with just over half of the 8TB used
1-drive, 2TB backup drive backing up the most critical data
Online backup backing everything
2 or 3 additional (currently spare) 2TB drives
What I'd like to do is have a local backup that captures everything. I am thinking of getting another Thunderbolt external enclosure but haven't decided if I want/need a 4- or 5-drive setup. Given the concerns with RAID 5, I am considering other setups such as RAID 10 or JBOD. The problem I see is that a 4-drive RAID 10 won't give me enough space for a complete local backup of the data I'm already using, let alone allow for any growth. I would also like to utilize the drives I have already, rather than buying new ones at this time. I don't have the budget for an 8-drive enclosure, so that rules out an 8-drive RAID 10 setup.
I'm thinking I could add a 4-drive JBOD or RAID 0 using the drive from my current local backup plus my spares on-hand and have that be my primary storage while the 5-drive RAID 5 becomes the local backup.
If this was your setup, what other enclosure would you get, and how would you configure it? Which would you have be the primary? Would you reconfigure the RAID 5?