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

Unlike VCS, Oracle Clusterware/Grid Infrastructure uses separate resources for
components that run in parallel on multiple nodes.
Resource profiles
Resources are defined by profiles, which are similar to the attributes that define
VCS resources. The OCR contains application resource profiles, dependencies,
and status information.
Oracle Clusterware/Grid Infrastructure node applications
Oracle Clusterware/Grid Infrastructure uses these node application resources to
manage Oracle components, such as databases, listeners, and virtual IP addresses.
Node application resources are created during Oracle Clusterware/Grid
Infrastructure installation.
Voting disk
The voting disk is a heartbeat mechanism used by Oracle Clusterware/Grid
Infrastructure to maintain cluster node membership.
In versions prior to Oracle RAC 11g Release 2, voting disk data exists on a shared
raw volume or a cluster file system that is accessible to each node.
In Oracle RAC 11g Release 2, voting disk data exists on ASM or on a cluster file
system that is accessible to each node.
The ocssd processes of Oracle Clusterware/Grid Infrastructure provides cluster
node membership and group membership information to RAC instances. On each
node, ocssd processes write a heartbeat to the voting disk every second. If a node
is unable to access the voting disk, Oracle Clusterware/Grid Infrastructure
determines the cluster is in a split-brain condition and panics the node in a way
that only one sub-cluster remains.
RAC extensions
Oracle RAC relies on several support services provided by VCS. Key features
include Veritas Cluster Server Membership Manager (VCSMM) and Veritas Cluster
Server Inter-Process Communication (VCSIPC), and LLT Multiplexer (LMX).
Veritas Cluster Server membership manager
To protect data integrity by coordinating locking between RAC instances, Oracle
must know which instances actively access a database. Oracle provides an API
called skgxn (system kernel generic interface node membership) to obtain
information on membership. SF Oracle RAC implements this API as a library
linked to Oracle after you install Oracle RAC. Oracle uses the linked skgxn library
41Overview of Veritas Storage Foundation for Oracle RAC
Component products and processes of SF Oracle RAC