Hot Online Backups

A Backup Article Contributed by Ashley Lister

Hot Online Backups

One of the many advantages that online backups have over traditional backups is there ability to provide "hot backups."

Hot Backups - Online.

"Hot backups" are those that can be performed without interrupting operators and users. More specifically, files can be backed up regardless of whether they are open, closed, being read or being written to.

Traditional Backups Versus Online Backups.

Ostensibly a proper backup regime should include an initial full system backup, where everything from the system registry through to the the smallest file is duplicated, followed by a series of differential or incremental backups. Differential or incremental backups are those that take copies of only the files that have been changed since the previous backup.

"Hot backups" operate in a number of different ways.

Some copy information direct from the file system rather than the device driver. These allow a backup to be conducted while operators are still accessing software on the machine but it is not the most reliable system available. While this style of backup is a comparatively swift method, it is also flawed. Any files that are open during the backup procedure will not be copied and, therefore, should the information in those files ever need to be retrieved it won't accessible.

Atomic backups are a more effective way of recording and storing information for later data retrieval but they are not technically "hot" and their limitations can be restrictive. Atomic backups lock each file before recording it for backup (online or otherwise). This can be an inconvenience if the file you are trying to work with becomes suddenly locked and atomic backups such as this run the risk of causing more problems than they ultimately solve.

The Importance of an Online Backup Regime.

A backup regime is important and an online backup regime is possibly one of the most effective ways of storing data for later retrieval. Knowing a little more about the technology that is used by online backup providers can never hurt in affecting your decision about which supplier to use.

Perhaps the most popular method amongst online backup providers, and certainly one of the most effective ways of backing up information, is through the use of a file system cloning program. In layman's terms, file system cloning is the process whereby "a snapshot" of the entire file system is taken at the time of the backup (online or otherwise). Then the "snapshot" itself is backed up (usually through an atomic procedure).

This method circumvents the problem of backing up open files because, whether a file is being used or not, the file system cloning program is only backing up the snapshot it has taken. That is why this system is so popular with online backup providers.

Not all online backup providers can supply facilities for "hot backups" so it is wisest to clarify your requirement before committing to a contract. However, because of the growing demand for this product, a lot more online backup providers are forging technology that will supply this niche in the market. Considering the cost of online backup, and the advantages it offers in so many other areas, it would be unwise to select any option that did not include this feature.