Technical Considerations for a Serviceguard Cluster that Spans Multiple IP Subnets, July 2009

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Definition of terms
The following terms and abbreviations are used in this whitepaper.
Table 1 – Terms and definitions
Term Definition
AutoFS
A client site NFS service that automatically handles NFS mount and umount
CTF
Connect Time Failover
–
Oracle client failover mechanism utilizing multiple protocol entries in tnsnames.ora at
connect time
DNS
Domain Name System
–
system to translate Domain Names into IP addresses
DWDM
Dense wavelength division multiplexing is a fiber
-
optic transmission technique that employs light wavelengths
to transmit data.
ECMT
Enterprise Cluster Master Toolkit
-
set of t
emplates and scripts that allows you to configure Serviceguard
packages for various applications; e.g.: Oracle single instance database
FAN
Fast Application Notification
–
Oracle application notification mechanism introduced with Oracle 10g
FCF
Fast Conn
ection Failover
–
Oracle client failover mechanism for JDBC applications introduced with 10g
FQDN
Fully Qualified Domain Name
GSLB
Global Site Load Balancer
GSS
Global Site Selector
ISL Inter-Site Link—A link between two sites that carries the cluster heartbeat and storage traffic
JDBC
Java Database Connectivity
–
type of Oracle client application
LDAP
Lightweight Directory Access Protocol
MAA Maximum Availability Architecture – Oracle's best practices blueprint based on Oracle high availability
technologies and recommendations
NIS
Network Information System
–
directory service protocol for distributing system configuration data such host
names
NFS Network File System – provides remote file system access over the network
OCI Oracle Call Interface – type of Oracle client application
SADTA Site Aware Disaster Tolerant Architecture
SGeRAC HP Serviceguard Extension for Oracle Real Application Clusters (RAC)
SGeSAP HP Serviceguard Extension for SAP
TAF Transparent Application Failover - Oracle client failover mechanism utilizing multiple protocol entries in
tnsnames.ora at re-connect time
TTL Time To Live – life time of a name resolution record
VIP Virtual IP address – IP addressed used by clients to connect to Oracle databases; controlled by Oracle
clusterware; similar to Serviceguard’s relocatable IP address
Defining cross-subnet support
As of Serviceguard A.11.18 with patch PHSS_37094 (11.23) and patch PHSS_37095 (11.31) or
later, Serviceguard allows a single cluster to span multiple IP subnets, with some cluster nodes on
different IP subnets from others. This is called a cross-subnet configuration. A cross-subnet
configuration allows:
 a heartbeat to span across multiple routed subnets, and
 automatic package failover from a node on one subnet to a node on another.