How does a backup administrator know exactly what data they need to back up?
Many administrators think they need to back up everything. But the truth is, you don't need a backup of everything on your system. Trying to back up everything can stretch your backup window and slow system performance.
Some kinds of data, such as .tmp files, can be automatically excluded from backups. Other data types, such as .mp3 files, shouldn't be on your system in the first place. Most backup software allows you to automatically exclude file types by their extensions. Many backup programs also allow you to make exceptions to the exclusions for particular users or departments who have a legitimate need for suspect data types and need to have those files backed up.
Applications generally need to be backed up much less frequently than data files. If you put the applications in separate volumes from the associated data and log files, you can reduce your backup times by backing up the applications less frequently. Depending on the specifics of your installation, you might be able to back up only 25% or 33% of your applications during full backup, and never back them up when performing incremental backups.
Some kinds of programs, such as e-mail archiving software and document management applications, can reduce backup requirements substantially by applying pruning techniques to that data. For example, e-mail archiving programs can routinely reduce the size of the message database by 50% to 70% using techniques like single-copy reference, in which only a single copy of a widely distributed e-mail is stored and then automatically referred to, rather than a copy being stored for each recipient.
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About the author: Rick Cook has been writing about mass storage since the days when the term meant an 80 K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last 20 years, he has been a freelance writer specializing in storage and other computer issues.
This was first published in February 2006