Set up system with RAID1 - how do I verify that files are actually being mirrored?

Legacy Products My Cloud OS 3
1

Just got the EX4 with 16 TB of WD drives.  Would like to verify that the mirroring is actually taking place.

2

pull all the drives save 1.  

that 1 should have all your data

what benefit do you get from writting the exact same data to all four drives and only 4 TB of working space? 

3

I thought that if I set it up with RAID 1, with 16 TB there would be 8TB of storage space, not 4.

4

Read the instruction manual more closely.

RAID1 is only supoprted as one RAID group per PAIR of disks.

So if you have 4TBx4 disks, you will have 4TB in the RAID1 group, and 8TB unallocated.

With that unallocated space, you will need to set up a second RAID1 group.