I have a ReadyNAS Duo that is about 2+ years old. Very good device. It is redundant with 2 Seagate Drives, each 1 TB. They are ST31000528AS drives. Firmware is current, 4.1.8. I don't think this unit can be updated to the Firmware 5.x.x series.
Drive #1 (the left hand drive) has been replaced twice. Each time the Reallocated Sector count started to increase. The current drive has started this same behavior. The Reallocated Sector count went from 0 up to 106 over the last 4 weeks. I removed the drive today and connected it to my PC and ran SeaTools to diagnose it. I used the DOS version so that Windows could not be interfering with the utility. I ran only the short test as frankly I didn't have time for the long test (hours). SeaTools found no errors and there are no ATA errors listed by the ReadyNAS. In the past the drives had failed the SeaTools tests. This one may do so in due course (I hope not!)
I'm wondering if the ReadyNAS itself could have a defect that might cause the drives in Disk 1 position to develop the need for Reallocated Sectors and ultimately fail. Has anyone else seen this behavior? If so, what, if anything can be done?
Finally, I'm wondering about the advisability of using SeaTools to erase the drive and let the ReadyNAS rewrite to it. Any thoughts on this would be greatly appreciated also.
I do keep full backups of the NAS as the data is important.
Thank you very much for any thoughts!