Regular writable optical media, CDs & DVDs, etc., are not reliable for long term storage. The die used with optical media degrade with exposure to light, temperature extremes, etc. Because of this, the data on the media will start to degrade within 1 to 5 years.
M-DISC (Millennial Disc) is a write once optical disc technology available in DVD and Blu-ray forms.
Millenniata claims that properly stored M-DISC DVD recordings will last 1,000 years, and are readable in conventional optical drives
Drives with M-DISC support and M-DISC Media