This document presents a variety of data backup methods. Comparing their respective
features will help you choose the best method for your organization.
Definitions
Byte: Unit of computer memory measurement
- Kilobyte (KB): Roughly one thousand times the
storage memory of a byte; average e-mail messages (without attachments)
will be under 10 KB
- Megabyte (MB): Roughly one million times the storage memory of a byte; a standard floppy disk holds 1.44 MB
- Gigabyte (GB): Roughly one billion times the storage memory of
a byte; the newest desktop computers can store
up to 20 GB
Compression: Shrinking data so that it can be stored using less memory capacity; data in this state must be decompressed to use again
CD Backup
Becoming a very popular means of backup.
There are two different CD formats:
- Recordable CD (CD-R): 650 MB, once discs are recorded, they cannot be written over, can be read from any CD-ROM drive
- Rewriteable CD (CD-RW): 650 MB, discs can be rewritten indefinitely, can only be read by newer CD-ROM drives
Advantages
- Prices for blank CDs have dropped considerably since they first came out.
Disadvantages
- CDs don't yet have as much storage capacity as some other popular back up methods.
If you are willing to put out more money up front, CD-RWs are becoming standard and are the better choice over CD-Rs.
Tape Drives
Generally recommended.
Advantages
- Relatively cost-effective for the level of reliability and efficiency provided
- High storage capacity
- Reliable in long-term storage conditions
- Generally simple set-up, lots of technical support available
As with many things in life, the more you pay, the higher quality
you are likely to receive. Still, with just a little searching, you
should be able to find a good quality tape system at a reasonable
price.
Network Backup
Can be highly effective.
Advantages
- Backups can be unattended and automated
- More capacity and more reliable than saving on floppies
- Cheaper than tape or removable drives
Disadvantages
There is one major drawback to using networks as a stand-alone
backup method. If the network server is housed in the same building as
the computers connected to it, then it is just as vulnerable to
physical damage.
Network and Tape Backup Combination
Even more highly recommended is a combination of network and tape backup.
Advantages
- Network can be programmed to automatically back up all the computers onto tape every night
- Tape is large enough to hold data from all the computers in the network
- Tape can be removed and stored in an off-site location
Web-Based Backup
Relatively new development, but seems promising.
There are now companies that will store your data online. Once configured for your needs, this can be a very convenient option.
Advantages
- Completely automated; no need to purchase or manage hardware
- Generally inexpensive
- Security: data is stored at an off-site computer
Disadvantages
- Security: you must be comfortable with someone else storing your data; verify the encryption and storage services of companies
- May not be ideal for very large (more than a GB) amounts of data
Removable Storage Drives
May be better than nothing, but not highly recommended.
All have storage capacity limitations that make the possibility
of unattendedbackups impractical. Prices range from moderate to
expensive.
- Large floppy-disk drive: at just over 100 MB, they offer the lowest amount of storage (e.g., Iomega Zip, Syquest EZ-135, LS-120)
- Removable
hard-disk-equivalent drive: at 500 MB to 1 GB, these devises offer
decent storage capacity and high reliability (e.g., Iomega Jaz, Syquest
SyJet)
Standard Floppy Disks
Not recommended for routine backups.
Disadvantages
- Cannot hold enough memory for unattended backup
- Could require using hundreds of disks per backup session
- Storage is unreliable; high likelihood of disk errors that can corrupt data
Although floppies have their downsides, they may be the only option
for some lower-budget organizations. Floppies are most effective when
storing small groups of related files.
Use a compression application to increase floppy disk storage capacity.
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