hot backup (dynamic backup)
Hot backup, also known as dynamic or online backup, is a backup performed on data while the database is actively online and accessible to users.
A hot backup is the standard way of doing most database backups. Oracle is a principal vendor of the process, but the company doesn't have a monopoly on the concept. Oracle Recovery Manager (RMAN) is the preferred method of backing up Oracle. A user can log in to RMAN and command it to back up a database. RMAN can write backup sets to disk and tape.
Advantages and disadvantages of hot backup
Hot data backups can provide a convenient solution in multiuser systems because they do not require downtime, as cold backups do. Unlike hot backups, cold backups have a defined window in which to pause the applications, shut the systems down and back up the data.
But hot backup involves certain risks. If the data is altered while the backup is in progress, the resulting copy may not match the final state of the data. In addition, online backup consumes read IOPS and can impact database performance if it is run at a time when the data storage is already under stress. Users may notice the hit as a temporary system or network slowdown.
Use cases for hot backup
When deciding on the type of backup, an IT administrator needs to weigh the downtime, but comprehensive nature, of a cold backup with the ability to keep applications available and productive through a hot data backup.
A hybrid backup option uses application-aware snapshots and application-aware data protection, creating a momentary pause and disruption to the application. The application continues to work, creating a virtual backup window.
When planning for backup or disaster recovery (DR) sites, particularly for failover and hot backup situations, it is important to think about the geographic scope of potential disasters. Business continuity and DR professionals should look for sites that are at least 100 miles away. This keeps local or regional disasters from knocking out a backup site as well as the primary site.
