Veritas Storage Foundation 5.1 SP1 for Oracle RAC Administrator"s Guide (5900-1512, April 2011)

to make ioctl calls to VCSMM, which in turn obtains membership information for

clusters and instances by communicating with GAB on port o.

Veritas Cluster Server inter-process communication

To coordinate access to a single database by multiple instances, Oracle uses

extensive communications between nodes and instances. Oracle uses Inter-Process

Communications (VCSIPC) for Global Enqueue Service locking traffic and Global

Cache Service cache fusion. SF Oracle RAC uses LLT to support VCSIPC in a cluster

and leverages its high-performance and fault-resilient capabilities.

Oracle has an API for VCSIPC, System Kernel Generic Interface Inter-Process

Communications (skgxp), that isolates Oracle from the underlying transport

mechanism. As Oracle conducts communication between processes, it does not

need to know how data moves between systems; the cluster implementer can

create the highest performance for internode communications without Oracle

reconfiguration.

SF Oracle RAC provides a library to implement the skgxp functionality. This

module communicates with the LLT Multiplexer (LMX) using ioctl calls.

LLT multiplexer

The LMX module is a kernel module designed to receive communications from

the skgxp module and pass them on to the correct process on the correct instance

on other nodes. The LMX module "multiplexes" communications between multiple

processes on other nodes. LMX leverages all features of LLT, including load

balancing and fault resilience.

Note: The LLT multiplexer (LMX) is not supported with Oracle RAC 11g.

Oracle and cache fusion traffic

Private IP addresses are required by Oracle for cache fusion traffic.

Depending on the version of Oracle RAC you want to install, you have the following

options for setting up your private network configuration:

Use either Oracle UDP IPC or VCSIPC/LMX/LLT for the database

cache fusion traffic.

By default, the database cache fusion traffic is configured to use

VCSIPC/LMX/LLT.

Oracle RAC 10g

You must use UDP IPC for the database cache fusion traffic.Oracle RAC 11g

Overview of Veritas Storage Foundation for Oracle RAC

Component products and processes of SF Oracle RAC