Today’s Question: Have you looked at and considered the use of Blu-ray drives and discs which purportedly can hold an enormous quantity of data and will never degrade in our lifetimes?
Tim’s Quick Answer: While optical media does have some advantages for archival data storage, there are also some concerns that lead me to personally prefer the use of external hard drives for primary, backup, and archival storage.
More Detail: Optical media often provides reliable long-term storage in terms of data integrity, and that is generally especially true of Blu-ray optical media. Blu-ray is effectively an updated version of the familiar DVD format, providing higher data density for higher capacity on a single disc.
Standard Blu-ray recordable discs are typically available in 25GB, 50GB, and 100GB capacities, though some higher capacity discs are available. Still, from the perspective of a photographer this is not a significant storage capacity compared to other media options such as hard drives.
There are higher capacity optical storage options available, including relatively high-capacity options specifically focused on data archive. For example, Sony offers an Optical Disc Archive Desktop Drive (https://bhpho.to/3lgh5VW) that can be used in conjunction with Write-Once Optical Disc Cartridges with a capacity of 3.3TB (https://bhpho.to/3k7wd8Q).
While optical media can generally provide great reliability for data storage, the discs do generally tend to be somewhat vulnerable to physical damage. In some cases, such as with the Sony drive noted above, the discs are enclosed in a housing to help protect the data disc. But there is still a degree of concern about physical damage to the discs even with relatively normal handling.
The bigger concern that makes me uncomfortable about using optical media for archival storage is the potential future lack of availability of drives for the specific media format you opt for. For example, most new computers do not come with a CD or DVD drive, let alone a Blu-ray drive. Standalone drives are available, but as has been the case with many other media formats in the past, I’m concerned that Blu-ray drives may become obsolete or at least somewhat difficult to find.
I therefore prefer to use hard drive storage for primary, backup, and archival storage. Even with external hard drives, of course, you need to make sure you maintain compatibility, such as to ensure the hard drive supports the available data connections over time.
Put simply, long-term storage of digital data requires a degree of maintenance over time, to ensure the media remains reliable and to ensure the media format is still supported. From time to time you may need to “upgrade” your archival storage to a different media format to ensure it will remain accessible.