At least that is what I was going to do....
Not sure RAID 5 gives me an advantage here... any thoughts? what is speed difference between RAID 5 and RAID 0 - is there one?.
I'm not an expert in this stuff, but here is what I understand, for whatever it's worth. For the same number of disks, RAID 0 will be faster than RAID 5. For example, a RAID 0 built from 4 striped disks, will be faster than a RAID 5 built from 4 disks. This is because part of every disk in the RAID 5 will be used for parity data, and the driver has to spend part of the time processing this parity data. Google will lead to several reviews of Thunderbay which compare various RAID configurations, and report data transfer rates for each. A good place to start is Lloyd Chambers'
site.
Your choice should be motivated by your priorities for speed, storage capacity, and fault tolerance. There are tradeoffs between these.
RAID 0 is really living dangerously. If any one drive fails, the entire array is hosed. RAID 0 is a good choice when working on large data files that must be streamed really fast, and where the data is transitory, or easily recovered from backup. People editing high-end video (multi-cam, 4K, etc.) are the natural customers for RAID 0. It's also a good choice for a Photoshop scratch volume, although if your boot drive is an SSD, it might be a better place for the scratch. If your data is in smaller chunks (requiring random access, lots of seeks) like a database, a programming project, or a multi-track audio recording with lots of samples, a RAID 0 might not provide much benefit, and might actually work less well than other options.
RAID 5 provides a speed boost, relative to a single drive, and the parity data provides a measure of fault tolerance. If one drive fails, you can run in a degraded state (slower, and with no tolerance for an additional drive failure) . When you replace the failed drive, the RAID rebuilds itself. That's the theory. But the rebuild can fail. Read
this for more information. The vulnerability of RAID 5 to rebuild failures is a subject of debate. But some IT pros are choosing RAID 6 (which requires an additional disk) to be on the safe side.
I'm using an SSD for my boot volume, apps, and working documents. The Thunderbay will hold my local backups and archive. For the disks in the Thunderbay my priority is data safety rather than speed. So I will use a RAID 1 mirror. This is more secure against faults than RAID 0 or 5. The RAID 1 will run at roughly the same speed as the member disks: 180MB/s, certainly fast enough for my needs. If I needed more speed, and the best fault tolerance, I would use a RAID 1+0.
For any of these RAID options, a separate backup is really required (preferably off site).