What is Oracle RAC used for?

Oracle Real Application Clusters (RAC) allow customers to run a single Oracle Database across multiple servers in order to maximize availability and enable horizontal scalability, while accessing shared storage.

What is scan and scan listener in Oracle RAC?

Answer: SCAN provides a single domain name via DNS), allowing and-users to address a RAC cluster as-if it were a single IP address. SCAN works by replacing a hostname or IP list with virtual IP addresses (VIP). SCAN is part of the 11g release 2 movement toward “RAC Virtualization”.

Why does Oracle RAC have 3 scan listeners?

As we know that the recommended value for SCAN ip using DNS/GNS is 3 SCAN IPS and this creates 3 SCan listeners randomly on the nodes. If we have a 5 node cluster then how many SCAN IPs are recommended.

What is scan name in Oracle?

Single Client Access Name (SCAN) is a feature used in Oracle Real Application Clusters. environments that provides a single name for clients to access any Oracle Database running. in a cluster. You can think of SCAN as a cluster alias for databases in the cluster.

What is difference between scan IP and VIP?

SCAN virtual IP addresses (VIPs) function like node VIPs. However, unlike node VIPs, SCAN VIPs can run on any node in the cluster. Clients (users or applications) that connect using a SCAN instead of a node VIP name or address do not have to update the list of node names or addresses in their local tnsnames.

What is the difference between scan listener and local listener?

The difference between SCAN Listener and Local Listener is SCAN listener runs corosponding to SCAN VIP’s while Local Listener runs with Node VIP or Node IP address. SCAN Listener can move to another database node in case of node failure but local Listener doesn’t have this kind of behavior.

What is the difference between VIP and scan IP in Oracle RAC?