One of the hard drives in my NAS reported too many sector reallocations, with a netgear NAS recognised the new HDD straight away and after 4 hours the data transfer was complete.. Breathed a sigh of relief because I have over 1200CD’s stored on there.
Make sure you get a drive that is on the compatibility list for your NAS. I was surprised how much faster this new drive is. It’s twin has been in service for over ten years so it’s probably time to replace that one as well.