X-RAID2 with two drives
Just thought I would clarify one misconception about X-RAID2.
If there are two identical drives, then the array is in fact RAID1.
No, not exactly. The array may be RAID1, but there are cases when there are two (or more) RAID1s, combined by LVM. This happens when a two-disk set is upgraded by replacing two drives with larger ones. If the array never had it's drives replaced, it is indeed a single RAID1.