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

■ Prevention of data corruption in split-brain scenarios with robust SCSI-3
Persistent Group Reservation (PGR) based I/O fencing or Coordination Point
Server-based I/O fencing. The preferred fencing feature also enables you to
specify how the fencing driver determines the surviving subcluster.
■ Support for sharing all types of files, in addition to Oracle database files, across
nodes.
■ Fast disaster recovery with minimal downtime and interruption to users. Users
can transition from a local high availability site to a wide-area disaster recovery
environment with primary and secondary sites. If a node fails, clients that are
attached to the failed node can reconnect to a surviving node and resume
access to the shared database. Recovery after failure in the SF Oracle RAC
environment is far quicker than recovery for a failover database.
■ Verification of disaster recovery configuration using fire drill technology
without affecting production systems.
■ Support for a wide range of hardware replication technologies as well as
block-level replication using VVR.
■ Support for campus clusters with the following capabilities:
■ Consistent reattach with Site Awareness
■ Site aware reads with VxVM mirroring
■ Monitoring of Oracle resources
■ Protection against split-brain scenarios
How SF Oracle RAC works (high-level perspective)
Oracle Real Application Clusters (RAC) is a parallel database environment that
takes advantage of the processing power of multiple computers. Oracle stores
data logically in the form of tablespaces and physically in the form of data files.
The Oracle instance is a set of processes and shared memory that provide access
to the physical database. Specifically, the instance involves server processes acting
on behalf of clients to read data into shared memory and make modifications to
it, and background processes that interact with each other and with the operating
system to manage memory structure and do general housekeeping.
SF Oracle RAC provides the necessary infrastructure for running Oracle RAC and
coordinates access to the shared data for each node to provide consistency and
integrity. Each node adds its processing power to the cluster as a whole and can
increase overall throughput or performance.
19Overview of Veritas Storage Foundation for Oracle RAC
How SF Oracle RAC works (high-level perspective)