I am planning on buying a readynas 516 + 2x expansion arrays for a total of 16 drives. Up front I will have 7x 2tb + 9x 3tb drives and I am would like to know how much USABLE space I will end up with. Also, is the limitation of not allowing smaller drives still true? If so I will start with a few 2TB drives, then add the rest of the drives as I migrate them from the curent nv+'s and the pro 6 that I currently have in to the new 516 array.
If I handle it like I have in the past I will: Start with 1x2TB drive in the array and upgrade the firmware, then add 3x3TB drives (so 1x2TB and 3x3TB - still need to be able to add 2TB drives later) and perform a factory reset. As I migrate data from my old NV+ devices I will remove the 2TB drives from them and add them to the new 516 (don't think it matters in the expansion or main array).
When the process is complete I will have all 16 drives spinning - 7x2TB and 9x3TB drives (all in the 516 + 2 expansion arrays).
The EDA500 will just be an extension of the RN516 so together with it, they will be considered as a single VOLUME. You can have one share on the whole XRAID volume spanning all the disks of the RN516 and the EDA500. Disk 1 thru 6 of RN516 and the remaining disks of the EDA500 will be raided together and then they will volumed together into a giant pool using btrfs filesystem.
It would seem that with XRAID2 it would be presented as one huge volume spanned across all the devices in 516 as well as the EDA500 expansion arrays as well (honestly this is my desired configuration). I really wish there was more documentation on the EDA500 to make a more intelligent decision :?
I don't think it would be advisable to set up one giant volume across 2 or 3 devices, even if this were possible, which I think it isn't. If one extension unit accidentally became disconnected the whole array would be compromised.
