Quote Originally Posted by ghosthunter View Post
But there are findings and reports even by the optical disc manufacturers themselves that the CDRs and DVDRs that are currently being manufactured and used for data backup only last two to five years.

The foil layer might last fifty years but the plastic itself is the one being degraded faster than expected. Some have "rot" starting from the disc's label design. Other problems have the laminate layers separating and causing the foil to corrode after exposure to air.

I very much agree that some discs do "rot" and "bronze" after only five years, or even less. This is because of substandard components used to manufacture either the recording substrate (which can tear or oxidize), the laminate, or the disc polycarbonate (which can scratch, shatter, or get misshapen).

The handling of the disc will also play a great deal in how long it will last. Repeated exposure to humidity, heat, light, changing temperature, and an acidic atmosphere (as well as acidic/oily fingers) will cause deterioration to set in quickly.

However, most of these suspect discs are the cheaper re-recordable/re-writable types. Archival quality discs are more resilient, with double foil layers (such as gold as the external protective film), thicker laminates, better polycarbonates, etc. This, coupled with careful storage and handling (gloved hands!), should present a relatively reasonable way to archive data. They're also more portable to lug around and the dangers of damaging it on transit are a bit less than a drive.

That said (and as oj88 correctly pointed out), it is a bit of a PITA to check a couple hundred of discs, so an alternative is to store data in at least two (preferably three) large capacity external hard disk drives. One (or two) will be stored safely as the master archive (foam-padded, humidity-controlled boxes, preferably different physical locations) while one can be for regular use. Just note that the internal lubricants of a drive can dry out after 5-6 years, so it might be a good idea to check on the master archive(s) at least once a year and on the 5th year or so, clone it to a new drive.