Are Blu-Ray recordable disks reliable and cost-effective for backups and data storage?

I seriously would recommend you get HDDs as a backup:

Reasons:

• They are cheaper
• You can keep your data always up to date
• You can plug them in anywere
• Faster Backup

If you check HDD prices today, they are probably quite high, this is still due to the flooding in Thailand, which made the prices for HDDs explode - doubled prices!

There is no perfect way to keep data, all media will degrade over time. The best way is multiple backups, probably on different media, kept on different sites to guard against fire, flood, etc.

200 BD-R discs * 2.40 = 480$

4 * Seagate Barracuda Green ST2000DL003 2TB 5900 RPM * 150.00 = 600$

If you set up a ZFS RAID-Z array, you would have 6TB of available space and one drive could fail completely, before you would be in trouble.