Blu-ray Disc (also known as Blu-ray or BD-R / RE) is the most advanced optical disc storage medium used today. The Blu-ray Disc has the same physical dimensions as standard DVDs and CDs, but it has considerably much more storage space, as a single layer Blu-ray Discs for Data Backup (50 GB of data for dual layer Blu -ray Discs). Since Blu-ray burning devices and storage discs will gradually get cheaper, backing-up to Bly-ray discs will increase in popularity to the point where it will surpass other backup methods, such as online back-up, because it is a convenient method and in the same time it can offer offsite protection (after you backup to Blu-ray discs, you can store those on a remote location).
A Blu-ray disc can have up to 16 layers, each of them being able to store 25 GB of data. If right now the most common Blu-ray discs only have one or two layers (meaning 25 or 50 GB), important players have announced that Blu-ray discs with capacities of 400 GB might be available to the public as soon as 2010. As capacity rises and prices will go down, the backup to Blu-ray method will become one of the most popular backup solutions.