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Digital Archiving

Provides guidance on organizing, archiving, backing up, and preserving your personal digital files in a variety of media formats, including text, photos, audio and video.


When your files are gathered and organized on a central computer, follow the 3-2-1 Rule when making backup copies.

The 3-2-1 Rule

3 – Make 3 copies

You central computer can count as one copy, but you should make two additional copies in case more than one backup fails.

2 – Use 2 different types of storage media

Rather than rely on the endurance of one type of storage media, make at least one of your copies in another storage format. 

1 – Store 1 back up in a different location

In case a physical disaster occurs, such as a house fire, keep one of your backups in a different geographic location, such as a relative's house in another state.

After you copy your files from your main computer to your backup storage, check to make sure that the files copied without any errors. One quick way to do this is to compare the total file size of the collection to see if there's any difference between the copies. Most computers have a Get Info feature (command-I or alt-click>Get Info) that will give you the total file size in bytes.

Storage Options

External hard drives

Storage devices come in desktop and portable varieties from commercial manufacturers such as Seagate and Western Digital. Hard disk drives (HDDs) are reliable and cheap for the amount of storage capacity, but they have moving parts that can break. Solid state drives (SSDs) are more durable, smaller, and faster, but can be expensive. Expect to spend around $50–$100 per terabyte of storage.

Cloud storage

When you store data in the "cloud," it's actually stored on servers owned by the service provider. Consider these factors when deciding on a cloud or file-hosting service:

  • Cloud storage requires a reliable Internet connection.
  • Cloud storage often starts out inexpensive or free, but there can be steep ongoing costs. What happens to your data when you stop payment?
  • Gradually adding data to a cloud account is easy, but does the service offer an easy way to get all your data out at once?
  • Where are the servers that host your files? How secure are they?

Physical Conditions for Storage Media

All digital data is encoded onto physical media which is itself susceptible to damage and degradation. For best results, digital storage media should be kept in the same kind of environmental conditions that you find comfortable:

  • Avoid extreme temperatures or changes in humidity. Maintain conditions around 70 degrees Fahrenheit and 40% humidity.
  • Avoid direct light, moisture, dust, dirt, mold, and pests. You probably also want to keep digital storage media away from powerful magnets.