You can use an SDS secondary database as a ‘hot standby’ server located on-site, to provide fast recovery in the event of local hardware failure.
Recovery using a standby server involves applying any outstanding transactions from active journals on the primary databases, if these remain accessible, and then switching processing to the secondary server while the primary hardware is repaired. (This is almost certainly quicker than the traditional methods of restoring from backup and then performing a roll-forward recovery.)