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

status by communicating over GAB and LLT. HAD manages all application services
using agents, which are installed programs to manage resources (specific hardware
or software entities).
The VCS architecture is modular for extensibility and efficiency. HAD does not
need to know how to start up Oracle or any other application under VCS control.
Instead, you can add agents to manage different resources with no effect on the
engine (HAD). Agents only communicate with HAD on the local node and HAD
communicates status with HAD processes on other nodes. Because agents do not
need to communicate across systems, VCS is able to minimize traffic on the cluster
interconnect.
SF Oracle RAC provides specific agents for VCS to manage CVM, CFS, and Oracle
RAC components like Oracle Grid Infrastructure and database (including instances).
VCS communication
VCS uses port h for HAD communication. Agents communicate with HAD on the
local node about resources, and HAD distributes its view of resources on that node
to other nodes through GAB port h. HAD also receives information from other
cluster members to update its own view of the cluster.
About the IMF notification module
The Intelligent Monitoring Framework (IMF) notification module hooks into
system calls and other kernel interfaces of the operating system to get notifications
on various events such as when a process starts or dies, or when a block device
gets mounted or unmounted from a mount point. VCS process-based and
mount-based agents use Asynchronous Monitoring Framework (AMF) kernel
driver that provides asynchronous event notifications to the agents that are
enabled for intelligent resource monitoring.
See “About resource monitoring” on page 36.
About resource monitoring
VCS agents polls the resources periodically based on the monitor interval (in
seconds) value that is defined in the MonitorInterval or in the
OfflineMonitorInterval resource type attributes. After each monitor interval, VCS
invokes the monitor agent function for that resource. For example, for process
offline monitoring, the process agent's monitor agent function corresponding to
each process resource scans the process table in each monitor interval to check
whether the process has come online. For process online monitoring, the monitor
agent function queries the operating system for the status of the process id that
it is monitoring. In case of the mount agent, the monitor agent function
corresponding to each mount resource checks if the block device is mounted on
Overview of Veritas Storage Foundation for Oracle RAC
Component products and processes of SF Oracle RAC
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