Follow the 3-2-1 File Backup Rule for Safe Data Storage
The 3-2-1 Backup Rule is a handy guide toward developing a sound data backup strategy. It recommends keeping at least three copies of our data, on at least two different types of media, with at least one copy stored offsite. The United States Computer Emergency Readiness Team (US-CERT) has published a short article that describes this in greater detail, along with the major pros and cons of various contemporary backup storage options.
Of course, if there's anything worse than no backups at all, it's backups that don't work! They lull us into a false sense of security. So it's a good idea to periodically test our backups. A good way to do this is to make a new, small test file, wait for it to be backed up, and then try to restore it.
There are many variations of the 3-2-1 Backup Rule. What's best in any particular circumstance is heavily dependent upon all the particulars. At UIC, Code42 CrashPlan offers faculty, staff, and students a great offsite option for backing up their personal computers (i.e., not servers).
Overall, the basic 3-2-1 Backup Rule, along with periodic test restores, constitutes a solid foundation for any good data backup, security, disaster recovery, and business continuity plan.
Special thanks go to Roger Deschner for his contribution to this article.