Degraded RAID 1 array - what to do first?

[condimentasm]

Hi all, I have two 1TB WD drives in my N2100 running RAID-1, and got an alert that the array is degraded:

The system [...] is suffering from disk problem.
RAID status is DEGRADED now. However, the data access is still functional.
Please solve the disk problem (e.g. replacing with a new hard disk).
The system will bring RAID back to the healthy state automatically.

Admin control panel > RAID > Config reports the following:
Disk 1: Status = OK, Raid = checked
Disk 2: Status = OK, Raid = unchecked

On the front of the enclosure, HDD 1 LED is blinking blue (active data transfer) and HDD 2 LED is off. Sooo I'm assuming Disk 2 is the bad one.

The only recent, unusual event was that I rebooted my router 8 hours before this happened. Not sure if that had anything to do with it.. I wouldn't expect so..?

Any advice on what to do first based on experience? Should I simply re-add Disk 2 and rebuild RAID, try to diagnose/fsck the disk, or simply pull and RMA it?

Thankfully the drives are both still under warranty ; )

cheers
Dave

[wengi]

Hi,

i had this once about one year ago.
I readded and rebuilt the raid.
Never had a problem again.
Ihave no idea why the thecus lost the 2nd hdd.

wengi

[condimentasm]

Thanks wengi.

I tried that and got the error "RAID created fail" so there must be a problem with the disk. Time to shut it down and do some diagnostics...