A backup schedule is an essential part of any data-protection strategy. You should design a backup system that is right for your situation and the data on your network. A number of different strategies can be used in backing up files. One way is simply to copy a file to another drive. Operating systems, however, typically have special backup commands that help you with some of the bookkeeping required for maintaining a systematic backup schedule. Most backup commands mark the file with the date and time of the backup so that you (and the backup utility) can know when a copy of the file was last saved. This is the purpose of the FAT file system’s Archive attribute. To determine whether this attribute exists, check the properties of any file on a FAT partition. If the Archive attribute is enabled, the file has changed since the last time a backup was done.

 

There are a few different methods of backup, they include:

Full backup. Backs up all specified files.

Incremental backup. Backs up only those files that have changed since the last full or incremental backup

A typical backup plan includes some combination of these backup types performed at regular intervals. One common practice is to perform an incremental or differential backup each  day and a full back-up every week.

 

Full backups make the restoration process easier because there is theoretically only one set of tapes from which to restore; however, they also require a lengthy backup process each night. This could mean that if the backup tape media is not large enough, someone must physically change the tapes, or there simply may not be enough time in the night to perform a full backup of all the data.

Another important step in your backup plan, therefore, is deciding where to store these backup tapes. Many companies choose to make two copies of each backup tape and store one of the copies off-site, thereby guarding against a catastrophic event such as a fire.

Tapes should not be stored near equipment that generates magnetic fields such as motors and the magnets in items such as speakers. Extreme temperatures and moisture will also be detrimental to the tapes.

When doing a backup the operator has the option of compression. This has its advantages and disadvantages. More data can be stored on the one disk, which would be very useful if the uncompressed data to be backed up is greater than the capacity of the storage tape. Due to the time taken to both compress and backup the data the process is slower for both the backup and restore functions. In this situation recovery times have to be considered along with the available time to complete the backup. The file formats will also be a consideration. Certain file formats such as .bmp and .txt respond to compression much better than .jpg or .gif formats.

Spanning is another possibility but it should be avoided. Buying a bigger tape backup unit is surely a better option than employing someone to manually swap the tapes when the spanning is due.

Keeping a log of all backups is important. Most backup utilities can generate a backup log. It is recommended that you make two copies of the backup log—store one with the backup tapes and keep one at the computer site. Always test your backup system before you trust it. Perform a sample backup, restore the data, and check the data to be sure it is identical to the original.

MAINTENANCE

A final point has to do with how long you wish to keep your stored data on the tape media. There is no correct time length. Some companies overwrite old tapes on a weekly basis, while others can keep their tape backups indefinitely. The correct time length depends on how important old data is to your firm. There is no simple answer to this question. As a rule of thumb it is suggested that a tape that is used on a daily basis should be discarded after 3 months.

Visual checks should be done to check for damage or distortion of the tape ribbon.

Tapes should not be stored on the top of monitors or near speakers and motors due to the damage caused by magnetic fields.