Devices
Hardware
Like
frequency of backups, there are no hard and fast rules regarding the
deployment of a backup device or backup media type. If your organisation is
small, and you work with very few files, it may be possible to save these to
floppy disks. SOHO (small office home office) users may use CD burning
technology to backup files, others may use an external zip drive, like the
Iomega Zip range.
These devices connect to the
parallel port or the USB port and are like floppy drives, except that the
earlier version holds 100mb and the newer version holding 250mb. It is also
possible to obtain internal versions of these drives, which require a spare
3.5-inch drive bay and an IDE connector. Also, some users favour a removable
hard disk drive for backup.
However, it is generally
accepted that tape drives are the devices of choice, and are certainly by
far the most popular, because they have the ability to store great
capacities of data at relatively low cost. There are a variety of media
types, the most common are listed here.
· Digital Linear Tape (DLT)
Among the newest technologies available, can store 70 gigabytes of data on a
single tape, and boasts transfer rates of 5Mbps.
· Quarter-Inch Cartridge (QIC)
Among the oldest of the tape formats. Capacity ranges from 40 Mb to 5
gigabytes. QIC tapes are among the most popular tapes used for backing up
personal computers, but rarely used for backing up network servers.
· Digital Audio Tape (DAT)
High-speed format most commonly seen in 4mm variety. Tapes are slightly
larger than a credit card and can hold from 2 to 24 gigabytes of data.
Transfer rates of about 2Mbps are supported.
· 8mm Cassette
Can store between 1 gigabyte and 5 gigabytes of data.
Procedure
The backup process is a
straightforward one. The administrator waits for a period of inactivity on
the network, usually after working hours when all users have gone home for
the night. This is so, for at least two reasons; the network will perform
sluggishly if the server is engaged in an intensive backup operation, and
users who have open files, will not be backed up, therefore a full set will
not exist.
The
tape drive, installed on the server (or attached externally to the server),
has a tape inserted. Next, the administrator opens his backup utility
software, which displays all files and folder on the server hard drive,
similar to that of the Windows Explorer. He then selects the various
folders, sub folder and files that he wishes to backup. He gives the back up
set a name, ensures that the tape drive is the target device, and then
clicks the "Run backup" or "Ok" button. The process is started. Once the
backup is complete, the administrator removes the tape from the drive, and
stores it offsite. Offsite storage is important, because the same flood or
fire, which would endeavour to destroy equipment, will also take out the
backups, nullifying the entire process. |
