# Backup Methods

**Back-Up and Test Your Back-Ups Frequently!**

** Always Run Scandisk and Defrag in Safe-Mode**

**Always Run Scandisk and Defrag in Safe-Mode**

**Tower Of Hanoi**

**The Tower of Hanoi backup method is based on a mathematical puzzle. A series of rings or disks are stacked in size order, the largest on the bottom, on one of three poles. The object is to move all of the rings to the third pole. But you can move only one ring at a time, and you can’t place a larger ring on top of a smaller ring. The secret is to shift the first ring every other move (moves 1, 3, 5, 7, 9, 11…), the second ring at intervals of four moves (moves 2, 6, 10…), the third ring at intervals of eight moves (moves 4, 12…), and so on.**

**The Tower of Hanoi backup rotation scheme lets you keep several current copies of data, several-week-old copies, and a few month- or year-old copies.**

**Each backup set is used a different number of times. When a new backup set is added, it is slated to be reused every other rotation. Older sets are used every fourth rotation, every eighth rotation, and so on. You can perform a set rotation daily or weekly. For example, if you have five weekly backup sets labeled A, B, C, D, and E, your backup rotation would look like this: A B A C A B A D A B A C A B A E (each letter represents a week of backups).**

**Round Robin**

**The Round Robin backup method uses a single backup set for each day of the workweek. This ensures that you will never lose more than a day’s worth of data, but it keeps only a week’s worth of your information.**

**Grandfather, Father, Son (GFS)**

**The GFS backup method is the most common rotation method. The number of sets you use is based on the number of workdays that you add data to your network. It works as follows:**

**Backup data on a different set every working day. If your backup cycle is based on a five-day workweek, you will need four daily backup sets (a fifth set comes into play later). You can perform full, incremental, or selective backups during the week.**

**On the fifth day, you will use a weekly set. You will need three weekly backup sets.**

**In the fourth week, you will need a monthly set. Since there are 13 four-week cycles in a year, you will need 13 “monthly” sets.**

**The GFS method is easy to use if you remember to label your cartridges whether a hard drive, cassette or tape. Also, since the daily backups are used more frequently than the weekly and monthly backups, you will need to replace them more often.**