Data Backup Software and Service

Many tools are available for backing up data. Some are fast and expensive. Others are slow but very reliable. The backup solution that's right for your organization depends on many factors, including

Capacity The amount of data that you need to back up on a routine basis. Can the backup hardware support the required load given your time and resource constraints?

Reliability The reliability of the backup hardware and media. Can you afford to sacrifice reliability to meet budget or time needs?

Extensibility The extensibility of the backup solution. Will this solution meet your needs as the organization grows?

Speed The speed with which data can be backed up and recovered. Can you afford to sacrifice speed to reduce costs?

Cost The cost of the backup solution. Does it fit into your budget?

Common Backup Solutions
Capacity, reliability, extensibility, speed, and cost are the issues driving your backup plan. If you understand how these issues affect your organization, you'll be on track to select an appropriate backup solution. Some of the most commonly used backup solutions include

Tape drives Tape drives are the most common backup devices. Tape drives use magnetic tape cartridges to store data. Magnetic tapes are relatively inexpensive but aren't highly reliable. Tapes can break or stretch. They can also lose information over time. The average capacity of tape cartridges ranges from 100 MB to 2 GB. Compared with other backup solutions, tape drives are fairly slow. Still, the selling point is the low cost.

Digital audio tape (DAT) drives DAT drives are quickly replacing standard tape drives as the preferred backup devices. DAT drives use 4 mm and 8 mm tapes to store data. DAT drives and tapes are more expensive than standard tape drives and tapes, but they offer more speed and capacity. DAT drives that use 4 mm tapes can typically record over 30 MB per minute and have capacities of up to 16 GB. DAT drives that use 8 mm tapes can typically record more than 10 MB per minute and have capacities of up to 36 GB (with compression).

Auto-loader tape systems Auto-loader tape systems use a magazine of tapes to create extended backup volumes capable of meeting the high-capacity needs of the enterprise. With an auto-loader system, tapes within the magazine are automatically changed as needed during the backup or recovery process. Most auto-loader tape systems use DAT tapes. The typical sys tem uses magazines with between 4 and 12 tapes. The main drawback to these systems is the high cost.

Magnetic optical drives Magnetic optical drives combine magnetic tape technology with optical lasers to create a more reliable backup solution than DAT. Magnetic optical drives use 3.5-inch and 5.25-inch disks that look similar to floppies but are much thicker. Typically, magnetic optical disks have capacities of between 1 GB and 4 GB.

Tape jukeboxes Tape jukeboxes are similar to auto-loader tape systems. Jukeboxes use magnetic optical disks rather than DAT tapes to offer high-capacity solutions. These systems load and unload disks stored internally for backup and recovery operations. Their key drawback is the high cost.

Removable disks Removable disks, such as Iomega Jaz, are increasingly being used as backup devices. Removable disks offer good speed and ease of use for a single drive or single system backup. However, the disk drives and the removable disks tend to be more expensive than standard tape or DAT drive solutions.

Disk drives Disk drives provide the fastest way to back up and restore files. With disk drives, you can often accomplish in minutes what takes a tape drive hours. So when business needs mandate a speedy recovery, nothing beats a disk drive. The drawbacks to disk drives, however, are relatively high costs and less extensibility.

Before you can use a backup device, you must install it. When you install backup devices other than standard tape and DAT drives, you need to tell the operating system about the controller card and drivers that the backup device uses.

Buying and Using Tapes
Selecting a backup device is an important step toward implementing a backup and recovery plan. But you also need to purchase the tapes or disks, or both, that will allow you to implement your plan. The number of tapes you need depends on how much data you'll be backing up, how often you'll be backing up the data, and how long you'll 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).