SCAN

1.1.1. SCAN The single client access name (SCAN) is the address used by all clients connecting to the cluster. The SCAN name is a domain name registered to three IP addresses, either in the domain name service (DNS) or the Grid Naming Service (GNS). The SCAN name eliminates the need to change clients when nodes are added to or removed from the cluster. Clients using SCAN names can also access the cluster using EZCONNECT. The Single Client Access Name (SCAN) is a domain name that resolves to all the addresses allocated for the SCAN name. Allocate three addresses to the SCAN name. During Oracle grid infrastructure installation, listeners are created for each of the SCAN addresses, and Oracle grid infrastructure controls which server responds to a SCAN address request. Provide three IP addresses in the DNS to use for SCAN name mapping. This ensures high availability. · · The SCAN addresses need to be on the same subnet as the VIP addresses for nodes in the cluster. · The SCAN domain name must be unique within your corporate network.