'Two Raid Group

I think providing this level of info in the GUI was a recent change.

When you vertically expand a volume (i.e. replace existing disks with higher capacity disks or add higher capacity disks to empty drive bays) it'll add an extra RAID layer to make use of the space on the higher capacity disks.

With X-RAID you need two higher capacity disks installed to begin to see vertical expansion (or 4 if using dual-redundancy - RAID-6).

Performance would be a little better with a single layer and if you unfortunately needed a data recovery attempt a single layer is a little easier to work with.

The initial sync when creating a volume is a lot faster than when rebuilding an existing RAID array. The disks still have to be synced sector by sector to setup the RAID.

Another advantage of a factory reset (wipes all data, settings, everything) is a clean install of the OS. Unless you restore a config backup afterwards any stuff left behind on the root volume from old firmware releases would be gone. We have made some significant changes over time in firmware updates including updating to a newer Debian distro.

The performance of the RN316 is a lot better than that of the EDA500.