ReadyNAS comes in a wide variety of RAID levels, none of them seemingly matching the standard. There are (in different ReadyNAS devices)
Flex-RAID is the most simple of them all. It is a stand-in for manual configuration. Once you choose Flex-RAID, the system asks you to choose between any of the standard RAID levels, and if you go for multiple arrays, then how many disks are allocated to each of the arrays.
X-RAID and X-RAID2 both hide RAID settings from user. Both will automatically expand array if more disks are added, or if enough disks are replaced with larger ones and the array can be expanded maintaining redundancy. Internally,
- on one disk, it is just a simple partition,
- as the second disk is added, that simple partition is converted to a RAID1,
- at the addition of the third disk, RAID1 is converted to a RAID5,
- as more disks are added, RAID5 is reshaped to accommodate additional disks.
The exact difference between X-RAID and X-RAID2 is sort of moot. For all intents and purposes, once the RAID crashed, they are the same.
Home NAS Recovery works with any of these configurations except
- where disks of different sizes are involved
- where multiple RAIDs are involved; Home NAS Recovery requires RAIDs fed to it one by one. If you have multiple RAIDs and you do not remember which disks form which RAID, your case is likely to end up in a data recovery lab anyway.