11g RAC over 10g RAC

From: https://sites.google.com/site/oraclerac009/b-rac-install-upgrade/11gr2-rac/11g-new-features-over-10g

11g RAC new features over 10g RAC

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. A) The Single Client Access Name (SCAN) is a domain name that resolves to all the addresses allocated for the SCAN name. Three IP addresses should be provided (in DNS) to use for SCAN name mapping as this ensures high availability. 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. B) The SCAN addresses need to be on the same subnet as the VIP addresses for nodes in the cluster. C) The SCAN domain name must be unique within your corporate network. 2) GNS In the past, the host and VIP names and addresses were defined in the DNS or locally in a hosts file. GNS can simplify this setup by using DHCP. To use GNS, DHCP must be configured in the subdomain in which the cluster resides. 3) OCR and Voting on ASM storage The ability to use ASM (Automatic Storage Management) diskgroups for Clusterware OCR and Voting disks is a new feature in the Oracle Database 11g Release 2 Grid Infrastructure. If you choose this option and ASM is not yet configured, OUI launches ASM configuration assistant to configure ASM and a diskgroup. 4) Passwordless Automatic SSH Connectivity If SSH has not been configured prior to the Installation, you can prompt the installer to do this for you. The configuration can be tested as well. 5) Intelligent Platform Management interface (IPMI) Intelligent Platform Management Interface (IPMI) provides a set of common interfaces to computer hardware and firmware that administrators can use to monitor system health and manage the system. With Oracle Database 11g Release 2, Oracle Clusterware can integrate IPMI to provide failure isolation support and to ensure cluster integrity. You must have the following hardware and software configured to enable cluster nodes to be managed with IPMI: A) Each cluster member node requires a Baseboard Management Controller (BMC) running firmware compatible with IPMI version 1.5, which supports IPMI over LANs, and is configured for remote control. B) Each cluster member node requires an IPMI driver installed on each node. The cluster requires a management network for IPMI. This can be a shared network, but Oracle recommends that you configure a dedicated network. C) Each cluster node's ethernet port used by BMC must be connected to the IPMI management network. If you intend to use IPMI, then you must provide an administration account username and password when prompted during installation. 6) Time Sync Oracle Clusterware 11g release 2 (11.2) requires time synchronization across all nodes within a cluster when Oracle RAC is deployed. To achieve this you should have your OS configured network time protocol (NTP). The new Oracle Cluster Time Synchronization Service is designed for organizations whose Oracle RAC databases are unable to access NTP services. 7) Clusterware and ASM share the same Oracle Home The clusterware and ASM share the same home thus it is known as the Grid Infrastructure home (prior to 11gR2, ASM and RDBMS could be installed either in the same Oracle home or in separate Oracle homes). 8) Hangchecktimer and oprocd are replaced Oracle Clusterware 11g release 2 (11.2) replaces the oprocd and Hangcheck processes with the cluster synchronization service daemon Agent and Monitor to provide more accurate recognition of hangs and to avoid false termination. 9) Rebootless Restart The fencing mechanism has changed in 11gR2. Oracle Clusterware aims to achieve a node eviction without rebooting a node. CSSD starts a graceful shutdown mechanism after seeing a failure. Thereafter, OHASD will try to restart the stack. It is only if the cleanup (of a failed subcomponent) fails that the node is rebooted in order to perform a forced cleanup. 10) HAIP In 11.2.0.2 the new HAIP (redundant Interconnect) facility is active and multiple interface selection will support load balancing and failover. You can select more than 4 interfaces for private interconnect at install time or add them dynamically using oifcfg.