Networking: A Beginner’s Guide Fifth Edition- P38:I have run into many people over the years who have gained good even impressive working knowledge of PCs, operating systems, applications, and common problems and solutions. Many of these people are wizards with desktop computers. | Chapter 12 Network Disaster Recovery 167 know this then it s probably the most important lesson that you can take away from this book. Making regular backups is a requirement when using computers period. You don t need to work with computers for very long before you observe firsthand the importance of good backups. Computers can and do fail and they sometimes fail in ways that render the data stored on them unrecoverable. Also some turn of events may cause certain important files to be deleted or corrupted. In cases such as these jobs are saved or lost based on the quality of the backups in place and the ability to restore that important data. Assessing Backup Needs Before designing network backup procedures you must understand the company s backup and restoration needs. Questions such as the following may help in assessing the needs that you must meet How dynamic is the data stored on the servers How often does it change and in what ways does it change How much data needs to be backed up and at what rate is the amount of data growing How much time is available to make the backup Make sure that you avoid situations where you need to back up terabytes of data using a system that can handle only megabytes per hour. If a partial or complete restoration from a backup is required how quickly must it take place As a rule of thumb restoring data takes about twice as long as backing it up although in some cases the times may be approximately equal. In other words if it takes your backup system 10 hours overnight to back up the entire network it will take 10 to 20 hours to restore that data and this estimate doesn t include the time required to resolve whatever problem made it necessary to restore data in the first place. How coherent does the backed up data need to be In other words does a collection of data files need to be handled as a single unit For example a directory containing a bunch of word processing files isn t terribly coherent you can restore one many or all .
