ReadyNAS Duo 2110 v1 - Unable to access

On frontview, go to Status > Health then click on Smart+ button for each drive. Check for Reallocated and ATA errors.

Do you have a backup of all the data stored in your NAS?
Did you received any e-mail notification that one of the drives is failing?

Do you have backup? I would suggest to check the disk using diagnostic tools like seatools or WD lifeguard.

Thanks a million to both of you. I am a real novice here and really happy to have you helping me out!

Yes, all NAS data is backed up!

After unplugging the NAS and starting up again, I was able to gain access through RAIDar. Went to Health and checked Smart+ buttons -- neither show any ATA errors. Disk 1 has no Reallocated errors but Disk 2 shows 3971. I did not receive any email notification alerts until I unplugged and restarted the NAS. Then I received an alert that "Disk 2 did not pass Smart assessment test ... replace asap".
Smart errors:
Previous count 0
Current count 3971

So I guess it's time to replace the drive. But that brings up a new set of questions:
1. If only one drive fails, is all my data secured on the other good drive? My current config shows as follows: X-RAID (Expandable RAID), 2 disks
2. After purchasing the new disk, do I just pull out the old one and hot swap the new one in?
3. Do I then have to "tell" the NAS to setup the RAID config again or will it do that automatically?
4. Anything else I should be aware of prior/during replacement?

THANKS AGAIN!

chuber wrote:
1. If only one drive fails, is all my data secured on the other good drive? My current config shows as follows: X-RAID (Expandable RAID), 2 disks

Since your NAs is on X-RAID, the data is still safe on the healthy drive.

chuber wrote:
2. After purchasing the new disk, do I just pull out the old one and hot swap the new one in?

Yes.

chuber wrote:
3. Do I then have to "tell" the NAS to setup the RAID config again or will it do that automatically?

The moment you hot swap the replacement drive, it should automatically procced with the resync process.

chuber wrote:
4. Anything else I should be aware of prior/during replacement?

Just wait until the resync process has completed then your data will redundant again. Check the compatible list of drives for the Duo v1: http://kb.netgear.com/app/answers/detail/a_id/20641

Ixa - you are awesome ... thanks again.

Currently, my two installed drives are both Seagate Barracuda 7200.12 (ST31000528AS) --- Specs of SATA 3Gbs and Cache 32MB.
I found a cheap replacement at Amazon but it is slightly different: Barracuda 7200.14 (ST1000DM003) --- Specs of SATA 6Gbs and Cache 64MB.
Will the difference in the drives cause a problem?

Thank you

About the ST1000DM003, kindly check this forum link for further info:
https://www.readynas.com/forum/viewtopi ... 4&p=371142

Phenomenal support!

I'm learning a ton here. I reviewed the link and recognize I need to be aware of the FW version if I purchase that drive. I also learned that the two drives installed now are not even the same (even though they were purchased at the same time and were in the exact same retail box)! The disk that is still working is a ST31000524AS and the failing disk is ST31000528AS. And even more interesting after reading the link you provided is that the failing disk has FW CC3E ... which I assume is an older version than the required FW CC4H.

You can mix/max different models as long as they are the same size. The ST1000DM003 is on the duo HCL.