Using Serviceguard Extension for RAC, 5th Edition, June 2007

Serviceguard Configuration for Oracle 10g RAC
Cluster Communication Network Monitoring
Chapter 2 73
• Serviceguard cluster configuration parameter
NODE_TIMEOUT
Then the CSS misscount parameter should be the greater of either:
• 195 seconds
or
• 25 times Serviceguard NODE_TIMEOUT + 15 seconds.
Limitations of Cluster Communication Network
Monitor
The Cluster Interconnect Monitoring feature does not coordinate with
any feature handling subnet failures (including self). The failure
handling of multiple subnet failures may result in a loss of services, for
example:
• A double switch failure resulting in the simultaneous failure of
CSS-HB subnet and SG-HB subnet on all nodes of a two-node
cluster. (Assuming the CSS-HB subnet is different from SG-HB
subnet). Serviceguard may choose to retain one node while the
failure handling of interconnect subnets might choose to retain the
other node to handle CSS-HB network failure. As a result, both
nodes will go down.
NOTE To reduce the risk of failure of multiple subnets simultaneously, each
subnet must have its own networking infrastructure (including
networking switches).
• A double switch failure resulting in the simultaneous failure of
CSS-HB subnet and RAC-IC network on all nodes may result in loss
of services (Assuming the CSS-HB subnet is different from RAC-IC
network). The failure handling of interconnect subnets might choose
to retain one node for CSS-HB subnet failures and to retain RAC
instance on some other node for RAC-IC subnet failures. Eventually,
the database instance will not run on any node as the database
instance is dependent on clusterware to run on that node.