Книга: Windows Server 2012 R2 Storage, Security, & Networking Pocket Consultant

Buying and using backup media

Buying and using backup media

Selecting a backup device is an important step toward implementing a backup and recovery plan. But you also need to purchase the tapes, disks, or both that enable you to implement your plan. The number of tapes or disks you need depends on how much data you have to back up, how often you need to back up the data, and how long you need to keep additional data sets.

The typical way to use backup tapes is to set up a rotation schedule whereby you rotate through two or more sets of tapes. The idea is that you can increase tape longevity by reducing tape usage and, at the same time, reduce the number of tapes you need to ensure that you have historic data on hand when necessary.

One of the most common tape-rotation schedules is the 10-tape rotation. With this rotation schedule, you use 10 tapes divided into two sets of 5 (one for each weekday). The first set of tapes is used one week, and the second set of tapes is used the next week. On Fridays, full backups are scheduled. On Mondays through Thursdays, incremental backups are scheduled. If you add a third set of tapes, you can rotate one of the tape sets to an off-site storage location on a weekly basis.

The 10-tape rotation schedule is designed for the 9-to-5 workers of the world. If you’re in a 24 hours a day, seven days a week environment, you’ll definitely want extra tapes for Saturday and Sunday. In this case, use a 14-tape rotation with two sets of 7 tapes. On Sundays, schedule full backups. On Mondays through Saturdays, schedule incremental backups.

As disk drives have become more affordable, many organizations have been using disk backup instead of tape backup. With disks, you can use a rotation schedule similar to the one you use with tapes. You will, however, need to modify the way you rotate disks to accommodate the amount of data you are backing up. The key task to remember is to periodically rotate disks to off-site storage.

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