Every application has its own level of availability requirement. Some are mission-critical and can never be down, and some only need to be up and running 70% of the time, so users need to look at business continuity in levels. Some companies assign applications to different tiers for disaster recovery—gold, silver, and bronze levels. |
Recovering data without making provisions for recovering applications is a lot like having the sheet music but no instruments, musicians, concert hall or conductor to play the symphony. It's just not going to get the job done. |
Some sophisticated applications have multiple modules writing to the same file, which can cause conflict. A server can lose power in the middle of a file being written, or a hard drive can fail. |