We will be acquiring a new NAS server for large capacity IP Video surveillance storage, both red and purple are listed in the compatible list from the NAS manufacture, which drive should I use and why…any help would be greatly appreciated
Hello there Jeremy 
I believe you will find this post very interesting and useful.
What NAS system are you getting? Are you using the NAS solely for video surveillance or you’d be doing other things on it too such as data storage and file sharing?
WD Red drives are designed specifically for NAS usage and RAID arrays and shouldn’t have any issues recording surveillance footage and you shouldn’t have issues, especially if you are using a RAID array that provides you with data redundancy. I’d recommend going for WD Red when it comes to NAS and RAID usage.
Captain_WD.
