Once a database failure is experienced, the database will have to be restored from backup, and possibly rolled forward. One point to note is that; unless replication is being used, it will be virtually impossible to bring the database right up to time. At the very least, the current online redo log file will be missing, and it is probable that a lot more will be missing. This will mean that all the missing work will need to be redone. So access to backups of the feed system data will be required. Some RDBMSs have support for hot standby databases. This allows a copy of the database to be kept in recovery mode, with archive log files being applied as they arrive on the disaster machine.