Optical media is the longest lasting medium currently in production. It can reliably hold onto your data for 50-100 years without power or cooling, and without the worry of magnetic degradation.
Using recordable optical media such as DVD-R is perfectly suitable for long-term archiving because it is write-once, read-many, meaning it is physically immutable—cannot be changed—so the data on it is tamper-proof.
It seems, then, that optical media might dominate archived storage, but it doesn’t. To explore why, first let’s take a look at the technology.
Source:: Network World – Data Center