Chapter 8: Business Continuity and Disaster Recovery - Data Backup

When backing up data, a company should use disk shadowing instead of disk mirroring because data can be stored on multiple disks. Electronic vaulting is another method of data backup that companies should use. Files are copied as they are changed, and from time to time they are sent away to a backup facility. Remote journaling can also be used. It is similar to electronic vaulting, but only the changes are backed up, not the individual files. The data can later be restored based on the changes that were saved. Another method, known is tape vaulting, is when the data is backed up on site, and then an individual physically transports the backup to offsite locations. When data is backed up in real-time it is a type of replication known as synchronous. On the other hand, when the backup up does not occur in real-time, or replicates later, it os known as asynchronous. High Availability means that a bunch of different technologies are used in order to ensure that databases and servers are always up and running, even after disaster strikes.