Digging into Hosting with ServiceNow

A ServiceNow-hosted instance is split over two physical datacenters, a high-availability pair. Each location runs independently of the other, giving a semi-clustered environment. In the event of a catastrophic disaster, with one location being completely unavailable, the other nodes will just pick up the load, with almost no downtime. In fact, the process of switching between locations is used for maintenance procedures, enabling your instance to be well-protected against hardware and other failures. When you visit your instance, you are directed through several layers:

·      By looking up the DNS records, you are directed to the currently active datacenter

·      The load balancer, by reading a cookie, directs you to the application server you have your session with

·        If you aren't logged in, you get directed to the least-busy application server

·  Your application server then uses the database currently determined as active