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Unnatended backup is most easily achieved by using tape automation technology. Tape libraries
usually feature one or more tape drives connected to a magazine. New tapes are automatically
fed to the drive(s) as needed, and existing backup tapes are loaded to the correct volume for
storage until such time when the information contained on them has to be restored. With the
appropriate backup software, tape libraries can be scheduled to do backups with no human
intervention. Such a product may have as few as 6 or as many as 80 cartridges.
When making a decision as to what type of a tape library an organization needs, the following
factors should be taken under consideration:
- Capacity: A small library may be sufficient today, but as the information contained
within the organization grows, so does the demand for storage space. Providing room to grow
and expand the backup system is a must. Larger capacity products also make the maintenance
easier -- the more cartridges in the library, the fewer times the administrator has to change
tapes. Tape libraries offering capacity in the range of several terabytes are not uncommon today.
- Number of drives: A single-drive library will be cheaper, but also slower and less
reliable then the multi-drive one. Parallel data streaming in multi-drive tape libraries
allows backups to be completed within smaller backup windows. Two or more drives per unit
provide a degree of fault tolerance, since of a drive fails, the remaining will be able to
finish the backup process. Some multi-drive tape libraries are capable of simultaneous
backup and restore, operating on different machines and volumes.
- Type of drive: The most affordable are the 4mm DAT tape drives. With capacity
ranging from 2 to 24GB (DDS-3) and transfer rates 400kb/s to 1.5Mb/s, their performance
has made them very popular in today's PC-based LANs.
The 8mm tape drives have a standard capacity of 14GB at a transfer rate of 1Mb/s, and are
a favorite for backing up larger networks.
The new 8mm Mammoth format, with a compressed capacity of 40GB and transfer rate of 6Mb/s
allows multi-drive tape libraries to reach the phenomenal transfer speed of 360MB/min or
more.
The 1/2" Digital Linear Tape (DLT) drives support capacities of 10 to 70GB (compressed) and
transfer rates of 1.5 to 6Mb/s. So far, this technology offers the greatest product flexibility
and tape shelf life (up to 20 years), but is also the most expensive -- a 40GB DLT cartridge
costs $150-200.
Tape automation is irreplaceable when disaster recovery is considered. But this technology
also makes people's lives easier, eliminating the element of human error (have you ever
overwritten important files with the information from the wrong backup tape? Or, have you
ever discovered empty tapes that were supposed to be full, containing the file you really
need?). Sometimes, this is the only way a backup can be acomplished, due to common extremely
narrow backup windows. No matter what the approach, your organization most likely depend on
its data more than we can emphasize it today...
Contact us to learn more about tape backup and tape automation technology and how we can help your organization implement it.
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