Entertainment · Design storage and backups · entertainment-10

Apply the 3-2-1 backup rule

One drive is not a library, it is a single point of failure. CISA's 3-2-1 rule makes sure one fire, flood or failed disk cannot wipe everything.

How

secure-18 is the single backup step for documents and data. Follow it for drive encryption and where the passphrase is kept. This step adds what is specific to a media library.
Keep 3 copies of the library: the working copy and two backups.
Use 2 different types of storage media, for example a server hard drive and a set of shelf drives (or an SSD, or optical discs for the most precious items).
Keep 1 copy off-site, away from the house: a neighbour's or relative's home, a separate outbuilding, or a secure store.
CISA also advises keeping offline copies and testing that you can actually restore files.
When you add files, make a checksum list (a file of hash values) for each folder. The NDSA preservation levels ask for fixity information when content is added.
NDSA Level 1 also asks for two complete copies that are not in the same place. The 3-2-1 rule goes further.
Backblaze's 2025 fleet data show an annualised failure rate of 1.36 percent for its hard drives: low per drive, but over many drives and years failures will happen.
Use the calculator's 'copies' input to buy enough drives for all three copies at once.

Back Up Business Data. US Cybersecurity and Infrastructure Security Agency (CISA), accessed 2026-11
Backblaze Drive Stats for 2025. Backblaze, accessed 2026-11
Personal Archiving: Digital Video. Library of Congress, Digital Preservation, accessed 2026-11
NDSA Levels of Digital Preservation (2013). National Digital Stewardship Alliance, hosted by the Library of Congress, accessed 2026-11