| The most basic type of disaster recovery is to | | | | Adding up the tapes you will have: 4 son tapes |
| copy all of your data to magnetic media and | | | | (assuming a five day work week), 3 father tapes |
| store it in an offsite storage location. In the event | | | | and a new grandfather tape every month. |
| of a disaster to the server or the entire building | | | | Six Tape |
| the data will be secure in an offsite location. The | | | | This scheme is the easier to implement but lacks |
| data can then be reloaded and business restarted. | | | | the redundancy of a GFS tape rotation scheme. It |
| The two most important considerations when | | | | is best used by small business with limited data |
| devising a disaster recovery plan is security and | | | | needs. Five tapes are labeled for each day of the |
| cost. Magnetic tapes are the most common | | | | week, assuming a five day work week. The sixth |
| option because they have a large capacity. In | | | | tape is also labeled Friday. A full backup is taken |
| addition, they are not-volatile which means they | | | | each Friday and an incremental on Monday |
| have a very long storage life. However, to get | | | | through Thursday. The Friday tapes are rotated |
| the life you expect out of magnetic tapes they | | | | and stored offsite. |
| should be stored in a media vault that controls | | | | Tower of Hanoi |
| temperature and moisture. | | | | This is the most secure tape rotation scheme but |
| The most basic tape rotation scheme is to | | | | also the most complex one. This scheme requires |
| backup your data every day for permanent | | | | five tapes labeled A, B, C, D, and E. The A tapes |
| offsite storage. This would work but requires a | | | | are used for a full backup every other day. The B |
| tremendous amount of tapes and storage space. | | | | tapes are used for a full backup every 4th day. |
| An incremental step is to only take incremental | | | | The C tapes are used for a full backup every 8 |
| backups. This only backs up the changes that | | | | th day. The D and E tapes are alternated for a |
| occur between the last full backup. This will reduce | | | | full backup every 16 th day. Or said another way, |
| the number of tapes for any backup and reduces | | | | tape A is used every odd numbered day. Tape B |
| the wear on the tapes. | | | | is used every other even numbered day. Tape C |
| Now since you don't want -- or need -- every | | | | is used every third numbered day. Tape D and E |
| backup, you can re-use tapes from prior periods. | | | | are used every fourth even numbered day. The |
| This is commonly known as tape rotation. Don't | | | | B, C, D and E tapes are stored offsite. Confusion |
| forget that tapes will wear out and need to be | | | | can arise because it doesn't operate on a |
| replaced periodically. You have reduced the | | | | traditional work week calendar. If you implement |
| number of tapes but there are more efficient and | | | | this scheme it is wise to have automated |
| secure rotation schemes. Here are three common | | | | reminders to help everyone keep track of what |
| tape rotation strategies: | | | | tape is to be used each day. |
| Grandfather - Father - Son (GFS) | | | | The most important thing for any tape rotation |
| This is the most widely used scheme for tape | | | | system is to get started. A poorly designed one |
| rotation. It combines security with ease of | | | | is far better than being left with no backup at all. |
| implementation. It's simplicity comes from running | | | | Keep at least one tape stored in a secure offsite |
| on a traditional calendar. On the last day of every | | | | location. Make sure the backup tapes are |
| month a full backup is performed and labeled | | | | accessible at all times. It is also wise to test your |
| 'grandfather'. This tape is stored permanently | | | | backups at least quarterly. What is critical data |
| offsite. On the last day of every week a full | | | | and where it is located can change and leave you |
| backup is done called the 'father' and stored | | | | missing valuable information when you need it |
| offsite. Then daily an incremental backup is done | | | | most. Do a full reload on a test system to see if |
| called the 'son'. Son tapes can be stored onsite or | | | | you can withstand a disaster to your systems. |
| offsite depending on the volume of data changes. | | | | |