Regular computer backups are essential for any business that relies at all on computers. While things may appear to be running fine, computer hard drives are notorious for failing catastrophically and completely without warning. To remedy this problem, a number of different backup systems are available for both large and small scale redundant data storage.
Backing up via Magnetic Tape
Magnetic tape is probably the oldest form of backup media still used today. Tapes have been around since before personal computing was born, but they are still a viable option because they can store a fair amount of data at very little cost. Popular tape formats include QIC (Quarter Inch Cartridge) and LTO (Linear Tape Open). One important thing to keep in mind about tapes is that tape storage is a linear medium. That means that, to pull anything off the tape, you have to fast-forward to wherever the correct file is stored. Because of this, tape systems are better suited for backing up or restoring an entire system in one go. For storing a few files or performing an incremental backup, tape drives are probably not the right choice. Another disadvantage of tradition tape storage is the fact that tapes must be physically loaded into and removed from the tape drive. Unless your company has the budget for an expensive autoloader system, you’ll have to assign somebody to do this on some kind of regular schedule. If that person forgets, you’ve missed a backup.
Second Hard Drives
The emerging alternative to tape media for whole system backup is the use of a second hard drive. Hard drives have dropped in price in recent years, and now they are competitive enough to replace tapes for many applications. While tape backup generally requires a backup schedule and a person dedicated to performing backup operations, extra hard drives can simply be installed in a PC and told to write anything sent to the main hard drive. In addition to simply writing redundantly to multiple disks, the hardware RAID level system provides several different backup and error-checking alternatives which are too complex to explain here. Hard drive arrays are the clear winners in companies where vast amounts of data is warehoused and processed. Terabyte hard drives have become much more common and typically cost less than $300, while providing years of backup space for most applications. Of course, the backup hard drives themselves can fail, so any mission-critical backup systems will require built in redundancy.
External Hard Drives
For backing up a single personal computer, a good choice might be an external hard drive. While they cost a bit more than regular hard drives meant to be installed directly into computers, external hard drives are more portable and can handle being moved from machine to machine. They also have the advantage of requiring much less technical skill to connect and disconnect. This means you can take one around to several computers if you need to back up some files from each one. Because external hard drives are essentially internal hard drives in hard plastic cases, they have the same basic strengths and weaknesses, the only difference being the portability of the external version and the backup software that is often bundled with the external drive.
Incremental Backup
Many computer backup systems these days use an incremental backup strategy, meaning that only new changes to the system are saved each time a backup is made. The advantage of this technique is that it speeds up the process of making regular backups, and can significantly shrink the amount of space required for each one. Incremental backups open up a whole new set of backup medium options because they tend to be so much smaller. In fact, many individuals and businesses use common, inexpensive writable CDs for most backup tasks. CDs are fairly durable and extremely cheap, making them a good choice for storing data up to about 700 megabytes. Many standard personal computers today already come with CD burners installed, so if you choose this option you may already have the equipment you need to get started.
For incremental backups up to about 8 gigabytes, DVDs might be a good choice. While slightly more expensive than a standard CD-ROM, a writable DVD is still fairly cheap, on the order of tens of cents. Like CDs, DVDs can only be written to once, but they hold much more data. Because of their low cost and high capacity, DVDs are a very popular backup choice for many companies and individuals. While some computers do come with DVD burners, you will probably need to purchase one, as they are still not standard hardware. The good news is that prices for both DVD and CD burners have dropped dramatically over the last few years, At the time this article was written, a new DVD burner can sell for as little as $50, and most are under $200. Automatic DVD burners capable of burning data to several discs without supervision are much more expensive, in the $1,000 dollar range.
USB Drive
Individuals looking to simply back up a few files have many more options to choose from. The humble but increasingly ubiquitous USB flash drive is a perfect candidate for many jobs. USB flash drives are fairly cheap, can hold several megabytes of data, and are very resistant to shock, temperature, and even being run through the washing machine. All flash devices have a limited number of read/write cycles, however for backup purposes this should not become a problem until the drive has been in use for a few years. Older technologies such as 3 1/2 inch floppy disks and Zip disks are still occasionally in use, but with the price of flash memory so low there is really no reason that they should be. Data on magnetic media such as floppies and Zips degrades predictably over time, making these media poor choices for any long term file storage.
Ultimately, the backup system you choose will depend on the amount of data you need to store and the frequency with which you need to perform backups. For very large scale backup systems, it’s hard to beat the price point of modern high capacity hard drives, while weekly backup systems for individual machines tend to rely on DVDs. Whatever solution you choose, be sure to buy from a company with a good reputation for producing reliable hardware. You don’t want your backup system to fail at the moment when you need it the most!