IBM is offering clients the world’s fastest
one terabyte storage tape drive,the IBM System
Storage TS1130, to help them protect and
archive more information with less cost and
less energy usage. Photo courtesy of IBM.

Most people understand the need for backing up their data and believe they are accomplishing that as they have a RAID array or they are doing mirroring or duplexing on their server.  If their server crashes, they have a backup, so why, they ask, do they need to have another type of backup system?

A RAID Array, mirroring and duplexing are all great ways to assist you with uptime.  Additionally, they do protect you when a hard drive fails, as they keep a current copy of your data. However, they are not enough. They replicate your current data. So data that has been deleted or has become corrupt is replicated as well. Furthermore, the proximity of these drives, to the original, means that in the case of problems due to theft, fire, water etc., you lose both the original and the copy.  

A backup system provides you with a history. Backups should be taken periodically, retained over time and stored off-site. Often data becomes corrupt and you may not realize it for months. Sometimes this is due to a virus.  The data on your mirrored hard drive will have the same corrupt data that is on your current hard drive. You have to go back in history to find a time when the data was not corrupt.  

Every company has to work out a schedule that makes sense to them.  The traditional industry standard way of backing up a server was a grandfather, father, son relationship which required 20 backup tapes (if tapes are what you are using), for a company that works 5 days a week.  

This means that you back up your server Monday through Thursday, with daily tapes 1 – 4. Then, you back up your server weekly, with weekly tapes 1 – 4. Finally, you back up your server monthly, with monthly tapes 1 – 12.  Many people then save a year end backup of the data. The tapes can all be reused, but you can go back and identify and correct problems for a year, relatively easily.  

One large business had a time entry program. Unfortunately, the data for the first quarter  became corrupt, but no one realized it until the 4th quarter.  There were no electronic backups as the company didn’t think it needed to retain data that long.  Therefore, they spent an enormous amount of time reconstructing the data. If they had a backup system that retained data for a year or more, this would not have been a problem. Often individuals delete a document or a file and find out months later they need it. Restoring the archived data is simple and easy.

More and more people are finding alternatives to tapes. Tapes are expensive and prone to problems. Depending on your size, you can use a USB hard drive and retain backup copies on it. You should use a minimum of 2 drives.

If your company is very small, or you are looking for a personal solution, you can do a full backup, for example, any time major changes occur on a USB hard drive and perhaps use aUSB thumb drive to back up the changes to your documents or personal accounting files weekly.