3-2-1 Rule of Backup

"There two groups of people: those who have already had a storage failure and those who will have one in the future." - Peter Krogh

In short, the 3-2-1 rule of backup means you must;

• Have at least three independent copies of your data.
• Store the copies on two different types of media.
• Keep one backup copy offsite.

 Read More: http://dpbestflow.org/node/262