470
Music industry’s 1990s hard drives, like all HDDs, are dying
(arstechnica.com)
This is a most excellent place for technology news and articles.
Hard drives offer the best price/capacity ratio, but they need to be powered periodically (at least once or twice per year). As with any other storage medium, include parity data and have multiple backups to avoid data loss.
Tape is too expensive.
Optical media can also be pretty good as long as you get discs made from inorganic materials and store them properly. M-disc is supposed to last like 100 years. The biggest problem is that they are on the path to obsolescence and optical drives may stop being manufactured. Also, it's a good idea to check on the condition of the discs periodically and redo any that shows signs of degradation (probably a good idea to replace non-M discs every 10 years regardless).
But regardless of the media, there is no archival method that doesn't require active maintenance, like periodically checking the data, ensuring you have multiple backups, refreshing any aged media.