Managing Serviceguard 13th Edition, February 2007

Planning and Documenting an HA Cluster
Hardware Planning
Chapter 4 141
When there is a primary and a standby network card,
Serviceguard needs to determine when a card has
failed, so it knows whether to fail traffic over to the
other card. The configuration file specifies one of two
ways to decide when the network interface card has
failed:
• INOUT
• INONLY_OR_INOUT
The default is INOUT.
See “Monitoring LAN Interfaces and Detecting Failure”
on page 104 for more information.
Kind of LAN Traffic
Identify the purpose of the subnet. Valid types include
the following:
• Heartbeat
• Client Traffic
•Standby
Label the list to show the subnets that belong to a bridged net.
Information from this section of the worksheet is used in creating the
subnet groupings and identifying the IP addresses in the configuration
steps for the cluster manager and package manager.
Setting SCSI Addresses for the Largest Expected
Cluster Size
SCSI standards define priority according to SCSI address. To prevent
controller starvation on the SPU, the SCSI interface cards must be
configured at the highest priorities. Therefore, when configuring a highly
available cluster, you should give nodes the highest priority SCSI
addresses, and give disks addresses of lesser priority.
For SCSI, high priority starts at seven, goes down to zero, and then goes
from 15 to eight. Therefore, seven is the highest priority and eight is the
lowest priority. For example, if there will be a maximum of four nodes in
the cluster, and all four systems will share a string of disks, then the