Abstract: An online system, such as a multi-tenant system ensures high availability of systems, for example, database management systems. The online system replicates the databases across multiple datacenters including: (1) a master node that receives read and write requests (2) a read-replica that receives only read requests and (3) a spare node that does not receive requests but acts as standby for high availability. One or more application servers may send read and write requests to the databases. The system performs a sweep of upgrades of the database nodes and also performs traffic quiescing of the requests received from the application servers to redirect the traffic across the database nodes as the upgrade sweep is orchestrated. The sweep of upgrades ensures that the availability of the database management system to the end users is maximized during the upgrade process.