Bits & Bytes: Keeping your data available
June 22, 2011
Many people have experienced the effects of some type of computer system failure. Even if you happen to have replacement equipment readily available, restoring settings, files, and programs is time consuming and these may never be restored to exactly the way they were before the failure. Keeping below the point of diminished return, there is no way to produce hardware that is incapable of failure, but there is a way to minimize, if not eliminate, the downtime, stress, and frustration associated with these failures.
"Imaging" is the process of saving the current state of your computer system. The current state includes the operating system, programs, settings, and documents of your computer system. Creating an image is an easy way to eliminate the majority of downtime associated with catastrophic failure.
Normally, without an image, such failures could require a complete reinstallation: a process involving installing the operating system, drivers, applications, restoring documents, and configuring the entire system to work the way you like it. This process can easily take five to six hours and produce days of downtime. If an image is available, however, this process is replaced with simple "re-imaging" which reduces days of downtime to a matter of minutes and brings the computer exactly to the state it was at the time the image was created. After the re-imaging, only files that were changed after the last image was created need to be restored.
Sometimes, there is not a catastrophic failure, but simple mistakes or minor errors that go unnoticed. The most common of these are accidental file deletions or file corruptions that go unnoticed because the files in question are not regularly accessed. In this instance, you may attempt to locate or open a file only to find that it is no longer available. "Historical" backups offer the solution for this scenario.
Historical backups are backups that are saved regularly to either tape or archival media using a number of cartridges needed to create the desired history. If, for example, you wished to retain a two week history of files that are changed every day, you would have 14 cartridges that are changed every day. At the 15th day, the first tape or cartridge in the set is reused. This allows a fourteen day buffer for you to discover errors with your files from which you can recover easily and quickly. Avoid using CD-R/RW, DVD-R/RW, or flash storage for historical backups as these media fail easily and are not designed to hold data reliably.
A thorough back up and imaging plan will minimize, if not eliminate, the downtime associated with equipment failure, thus maximizing the availability of your data.
(Bits & Bytes is a computer troubleshooting advice column provided by Zebis, a single point of contact managed service provider located on Sanibel serving clients worldwide.)