Adding Raid Storage To Exacq Z Series?

I have read a few discussions on IPVM on adding storage to other series of recorders and using standard WD Purple drives in non Raid applications.

My question is, are the WD purple drives also sufficient for a Raid setup or will that require the WD Purple NV drives?

What is a cost effective yet reliable solution to expanding storage on a Z series. I am an intrusion, Access guy but not much of a PC based video guy.

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