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Is Your Backup Data Complete?
- Here are three tape rotation schedules to help you keep your data
Your backup tape rotation is just as important to the life of your data as creating it in the first place. Tapes fail; it’s the unfortunate little secret in the backup business. The worst part about it is you may never know when a tape has failed until you’re trying to retrieve data from it in a catastrophic situation. In addition, files get deleted – either by accident or just because someone thought they didn’t need it anymore. They may also get corrupted by viruses, power fluctuations and outages, or any other typical PC wear-and-tear. Keeping a good rotation is imperative so that you will always have a recent backup to restore all your data and an older backup to find that missing file.
There are three recommended rotation schedules for tape backups. They range from good (easiest) to best (intricate). You should choose the rotation schedule that best fits the value of your data. Some companies are okay with losing data from before two weeks ago (easiest) and some need to be able to get a file from, say, June 2006 or earlier (intricate but best). A common theme through all the plans is to have at least one tape off-site at all times. A backup tape does no good if it’s burning in a fire (or melting in a fire-proof safe).
The Good
The easiest and least desirable tape rotation (but still acceptable) is the ten-tape rotation. This is simply ten tapes, each labeled with a day of the week, rotated daily. This process ensures you always have data to go back to from the last two weeks. Click here for a diagram of the Ten Tape Rotation.
It is necessary at the end of the day to take home the tape you just took out of the drive. That way in case of fire or other catastrophe, you won’t lose a recent copy of your data along with the rest of your business. And don’t forget to clean your tape drive! On a ten-tape rotation it is a good idea to clean your tape drive at least once per rotation. Also you will need to replace your tapes once they start to wear out from use (about once per year).
The Better
A better rotation solution involves purchasing another five to ten tapes. In order to remain alliterative (and because it’s better), I’ll recommend twenty total tapes for the twenty-tape rotation. This is similar to the ten-tape rotation, except every other rotation (every four weeks) you archive one tape.
Label the tape to be used on the second Friday of the rotation as “archive” and leave room on the label for a pencil mark. Mark each time you use that tape and after two marks place the tape in a safe place-- preferably at a location other than your office. Then take another blank tape, label it "archive" and place it into the rotation. After you use your ten “archive” tapes, bring the oldest archive tape back into rotation, erase the two pencil marks and start over. Here is a diagram of this process.
Remember that cleaning your tape drive is very important. I would clean the tape drive at the very least once every two weeks. And, once again, you will have to replace those core rotation tapes -- they will wear out much more quickly than the archive tapes.
The Best
The most intricate and effective rotation method continues to build on the first two. It is simply the Twenty-Tape Rotation except you never reuse your archive tapes and you add one yearly archive tape. In order to do it properly, you need to start with at least twenty-three tapes. However, since the point of this rotation is to have archive tapes from years in the past, you will need a lot more than twenty-three tapes total. If you want to go back seven years, for example, you should have at least 107 tapes.
Just like the twenty-tape rotation, you will have nine tapes labeled Monday-Friday with the exception of your “archive” tape. Since there are actually thirteen groups of four-week periods in a year you will need thirteen “archive tapes” per year. On top of that, you will need one yearly tape.
Follow the Twenty-Tape Rotation schedule for your archive tapes and follow this diagram. When it comes time for your yearly backup, consult your network administrator to help make sure you have a complete, successful backup. Then place that yearly tape in a safe-deposit box. You want to make sure that if both your office and “archive” storage facility burn down you can always have a yearly backup to turn to. And don’t forget to clean your tape drive and replace your core rotation tapes!
Things to Remember
Remember that tapes are more likely to fail the older they get. Replace your tapes according to the manufacturer’s suggested schedule. And clean your tape drive!
Backing up your data is always precarious -- no solution is ever 100% guaranteed. The more ways you backup your data the better chance you’ll have of restoring it.
Don’t forget your most valuable resource for answers about backups – your Network Administrator and IT Company. Give us a call or email us via our Contact Us page and we’ll answer all of your questions about backing up your data. Our online backup software makes an easy and cost-effective secondary backup solution. We'll make sure you’re as prepared as possible for any situation.