Question 1

What is the largest supported hard drive size usable in the NSA3200?

Accepted Answer

Per ZyXel's website, 2tb/per bay 4tb max.

Question 2

How does remote access work? Can I have it constantly as a mounted drive on my macbook pro?

Also, will it play nice with my Airport Extreme?

Accepted Answer

I have four of these units for data with 1-TB x 2 drives each, they have internet connections saving all our data in duplicate raid with no problem. Best bang for the $, don't know about Mac nor Airport Extreme but they work great in our office.

Question 3

I have a HD that was used in a different NAS.  Can this drive be used without reformating in this  NAS?

Accepted Answer

It shouldn't make any difference. 
In General terms because I don't use this box, if the drive is inserted as a replacement (Swap for dead drive) or a new added drive in an existing RAID, the system will handle any formatting issues as part of the rebuild process. 
If this is a new NAS the system setup will format all the drives according to the RAID Level you choose, all existing data is removed during that process.
I just moved three drives from an UNRAID server to a NAS and it went smooth as glass.
If your drive is over 3 years old consider using new drives. They do wear out. Yes I have drives that are older and still working too but don't be cheap if data security is important.

Questions & Answers