Just wanted to let you know that I used some of the procedures you listed on the site to upgrade my WD NAS. I had a working dual 500g system and I got both drives swapped out and now it is working with dual 1tb drives. It took some time and playing around, but if I had to do it again, it is actually pretty easy.
Summary of what I did. (my dual 500's where working so I didn't have to do some of the backup/recovery stuff).
- pulled one 500 drive and put it in my computer
- backed up the single 500g drive from WD NAS to 500g drive in computer as a just-in-case
- put the 1tb drive into NAS as the second drive to the 500g and did a rebuild
- booted my computer with knoppix and just the 1tb drive I rebuild connected (no other drives AT ALL)
- deleted partition 4, recreated it with fdisk using rest of disk, formated it
- updated UUID in config file on 1st partition
- put it as first and only drive in WD to make sure it booted
- then added second new 1tb drive, rebuilt
I now have a dual 1tb drive WD NAS! Thanks for the FAQ page and steps/hints to get my NAS upgraded to bigger drives. If anyone has questions, let me know.