[NV+ v2] 4 disks, 2 separate RAID-1 volumes?

But, had you gone with X-Raid2, you could have put the 2x1.5 TB drives in for a total of 1.5T and now added the 2x3TB disks which would on expansion given you 2x1.5TB + 1x3TB of space for your volume for a total of 6TB of data space (1x3TB for redundancy). So, you are wasting the 1.5TB of space of one drive used for redundancy in two Raid-1 volumes that would not be used for redundancy in an X-Raid/2 volume. My volume started with 2x500GB drives in 2007 in an NV+, expanded with a third 500GB and a 750GB for a total volume of 1.5GB. I then added an NVX with 4x1TB and then replace the NV+ drives with all 1TB for a volume of 3TB. I later replace two of the 1TB drives with 3TB for a 2x1TB and 2x3TB volume with 5TB gross volume (4.5TB net).