Real-Time vs. Daily Backup

by Lowell Rapaport

As storage area network technology matures, real-time backup is becoming a more practical option.

Most companies back up their files once a day. The backup is incremental, meaning only files that have been created or modified since either the last full backup or the last incremental backup are copied. Real-time backup, on the other hand, copies files to a secondary storage device as they are created or modified. The result is a mirror of all files kept in storage.

The advantage of a real-time backup is that files are continuously, rather than periodically, backed up. If your primary storage system goes down, you won't have to recreate even half a day's worth of files. Also, if your primary storage center is destroyed, you can be up and running again in the time it takes to bring the backup storage online.

Real-time backup may seem reminiscent of a feature found in many optical archive management systems, which have long offered the ability to copy optical volumes in real time by making two optical discs at the same time - copying an optical disc as soon as the physical volume is closed.

Real-time backup is most effective when the backup storage is kept in a remote location. The latest ISCSI technology lets files be transferred to remote locations over inexpensive Internet connections without complex reworking of storage management software.