2x 2TB WD green in ReadyNAS Duo?

You're correct about backups and disk reliability, of course. Which is why (per your earlier advice, BTW) I back up the important data on my readynas ultra plus to my old, but still functional, NV+. I have a USB backup as well. But even with backups disk failures are a pain (or worse) and the fewer episodes one has to deal with the better. My current troubles did in fact include complete failure of my readynas, which, fortunately, was reversible.

There really is an issue with the LCC which Netgear needs to address. Several WD "green" drives (the 3TB WD30EZRS and the 2TB WD20EARS drives, for example) are on the official Readynas HCL and have the LCC issue.

WD does not endorse these drives for use in a NAS Raid device. The major issue seems to be the LCC. Out of the box, these drives will run up a LCC of over a million in less than a year when installed in a Readynas. WD states that the drives have only been tested with LCC's of a million, over this is uncharted territory.

The way to fix this, if indeed it needs fixing, is to mount the drive on the internal SATA port of a computer that can boot DOS, and run the WD utililty wdidle3. But this is inconvenient, and may be beyond the technical expertise of many users. And, of course, it requires a suitable PC.

So, since the drives are on the HCL, I think Netgear needs to address whether the high LCC count is likely to reduce the drive lifespan, and if it is, I think they should try to prepare a readynas based solution that does not require mounting the drive in a PC and running wdidle3 (which requires booting in to DOS)