Choosing Backup Media

A Backup Article Contributed by Andrew Whitehead

Considerations in Choosing Backup Media

Matching the capacity of the backup medium to the amount of data you intend to backup is very important, especially as hard disks capacities grow. The more disk or tape swaps required to perform a backup, the less likely it is that you will do it routinely. ideally, the whole backup will fit on one tape or disk so that you can leave it to run and do something else. You don't need to back up the whole hard disk every time, so a backup media that can hold most of it will usually suffice.

Optical Backup Media

CD-R have a capacity of about 650 MB, and despite not being reusable some people use them for backup. One big advantage is that the backups are readable by any CD-ROM drive, but even though the cost of an individual disc is low it can still become a very expensive way to do backups if you need several discs per time.

CD-RW are a good flexible, reusable, general-purpose medium that is certainly usable for backup. It has disadvantages; the capacity is only average at 650 MB, and the CD-RW disks are essentially proprietary in that only compatible reader software can read them.

Tape As Backup Media

Backups are large, sequential writes ideally suited tape drives, and tape is making a comeback as a backup device. As hard drives keep growing tape is the only medium of a similar capacity that is growing to match them. For the drives, and per-gigabyte basis for the media, it is inexpensive. It is reasonably reliable, simple to set up, and has a lot of support for drives and software. Performance can be less than ideal, especially when random access is needed to specific files on the tape. Usually this only needs to be done when restoring data.

Using Removable Drives for Backup

Removable Hard Disk Equivalent Drives such as Iomega's Rev drive or various portable hard drives, have a large enough capacity to be suitable for backups. These drives have a reasonable performance (about twice the speed of a CD/DVD drive) and good reliability. The disadvantages are that they are proprietary and expensive.

An interesting backup method not often used is removable hard drives. The price per gigabyte of hard disks is compares favorably to drives such as the Iomega Rev and they give a very high performance, random-access capability, standard interfaces and exchangeability, and excellent reliability. The disadvantage is that additional media means buying an additional drive, and often removable drives can only be removed with the power off.

Network Backup

For networked PCs, copying data over the network from one PC to another is a viable alternative to using removable drives. By duplicating each PC's information it is possible to protect each individual PC without the expense of tape drives or removable storage. Disadvantage are that viruses can travel over a network, and if all the PCs are in one building there is no off-site storage. A better solution is to use a centralized removable storage backup device to automatically back up all the PCs connected to the network.