Well, if I remember correctly when I switched from one 4TB drive in JBOD to two 4TB drives. After I put in the second drive nothing happened (dont think its supposed to).
I could go to Drive Status and see both drives but I could not see the second drive anywhere else in the dashboard. I then went into the RAID section and selected to change the RAID. I was then presented with the option to choose what type of RAID I wanted. I chose to migrate to RAID1 and it then asked me to select the drives I wanted to include in this RAID1 volume and I selected the new 4TB drive I had just added.
As for the question about the price of 4TB drive, I got mine for $160 and it is a WD RED (NAS) drive.
I can say this after having the drive for a few months now that the Ex4 seems to be a decent NAS but the longer Ive had it the more its looking like it wasnt the best choice to go with. WD is a hardware manufacturer, who ever they have developing their software they need to find somebody new. Simple things here and their can be fixed easily with a firmware update and go a very long way. Even for someone like me who knows what they are doing, some of the things WD is doing is just flat out strange and confusing as to what they are trying to do. For example when you add a new drive and go to change the RAID from RAID0 to RAID1 the site allows you to check two check boxes. One says migrate and the other said something like switch to RAID1. The average user would see switch to RAID1, select that and hit next, or select both and hit next without checking the little info button next to the Switch to RAID1 option that says by selecting “Switch to RAID1” all of your data will be lost. Why couldnt they have just put a simple question like “Do you want erase the containts of all drives?” and then just given the choice of yes/no?
WD, get your act together because at this rate my next NAS will not be a WD.