XRAID 2

k3v1n wrote:
I am trying to maximise the amount of space in the NAS .... I could do 4 x 2TB or I could do 2 x 2TB and 2x 3TB alternatively I could do 3 x 2TB and 1 x3TB, I assumed if I put in 2 x 2TB and 2x3TB that it would raid one the volumes or is it likely to raid 5 but at 2TB ??

The largest sized disk in your NAS will not contribute to your usable space... So 4x2TB will give you 6TB usable, and 3x2TB + 1x3TB will also give you 6TB usable. 2x2TB + 3x3TB will give you 7TB usable, so you should use that combination.

All these numbers are approximate (and higher than you will actually see) because

• the size reported by the NAS and by your operating system is in TiB (one TiB = 1,099,511,627,776 bytes), but the sizes of your drives are reported by the drive manufacturer in TB (1TB = 1,000,000,000,000 bytes)


• there is some overhead -- 1 or 2 percent -- required by the RAID array.

Regardless of the exact numbers, though, 2x2TB + 2x3TB will give you around 16% more space than you will get with the other two combinations.