ReadyNAS Duo v1 HDD replacement problems

I bought a WD20EFRX NAS HDD and that has been working without problems.

I was wondering if the 2 drive bay slots function differently. I thought that the Duo could be configured in one of two ways: (1) the first with the total capacity being (size of HDD1) + (size of HDD2) and no redundancy and (2) the other being (the smaller size of HDD1 or HDD2) times 2 with redundancy. However, I don't see anyway of changing the configuration to no redundancy.

With that said, since it seems to always be configured with XRAID redundancy, does drive bay slot 1 always function as a "desktop" HDD and drive bay slot 2 always function as a "NAS" HDD (formatted with the XRAID redundancy)? Whether this is the case or not, I'm not sure how to restore the system if either HDD1 fails or if HDD2 fails. I haven't come across any procedures that explain the process of recovering from either one of those types of failures.

Also, if the two drive bays slots do indeed function differently (slot 1 as "desktop" HDD and slot 2 as "NAS" HDD), then would the Seagate ST2000DM001 HDD that I was trying to use in slot 2 work properly in slot 1 (since it is listed in the Hardware Compatibility List)?

My Duo originally came configured with one 1TB HDD. My first task was to add a second HDD for redundancy. In doing so I wanted to also upgrade the storage capacity to 2TB, so the second HDD I bought was 2TB. From reading the documentation, I understand that in a redundant system, the total capacity is going to be limited by the smaller of the two HDDs (in this case the original 1TB HDD). After the second redundant HDD fully installed (initialized and sync'd) and when the original disk is replaced with a 2TB HDD, it is my understanding from the documentation that the system will detect that both HDDs are 2TB and will report the total capacity as 2TB. Am I correct in my understanding?

In summary (and to be clear what I'm asking),

• Do the two drive bay slots in the ReadyNAS Duo v1 function differently, more specifically does slot 1 always function as "desktop" HDD (containing OS + data) and slot 2 always function as "NAS" HDD (containing XRAID redundancy of "desktop" HDD)?


• If the answer to the above question is "yes", then would the Seagate S2000DM001 HDD I first tried in slot 2 working properly if used in slot 1 instead and using my new Western Digital WD20EFRX NAS HDD slot 2?


• What are the procedures for restoring the system when either of the HDDs in slot 1 or slot 2 fail?


• In going from a system configured with (HDD1 = 1TB) and (HDD2 = 2TB) to a system configured with (HDD1 = 1TB) and (HDD2 = 2TB), will the system detect and report that the total storage capacity to be 2TB?

Thanks in advance!
John