2.2.4.1 Using Solaris Interface Groups

A new feature called interface groups was added to the Solaris 2.6 operating environment. This feature is implemented as default behavior in Solaris 2.6, but as optional behavior in subsequent releases.

As described in the ifconfig(1M) man page, if an interface (logical or physical) shares an IP prefix with another interface, these interfaces are collected into an interface group. IP uses an interface group to rotate source address selection when the source address is unspecified, and in the case of multiple physical interfaces in the same group, to distribute traffic across different IP addresses on a per-IP-destination basis (see netstat(1M) for per-IP-destination information).

When enabled, this feature causes a problem with switchover of logical hosts. The system will experience RPC timeouts and the switchover will fail, causing the logical host to remain mastered on its current host.

Interface groups should be disabled on all cluster nodes. The status of interface groups is determined by the value of ip_enable_group_ifs in /etc/system.

The value for this parameter can be checked with the following ndd command:

# ndd /dev/ip ip_enable_group_ifs

If the value returned is 1 (enabled), disable interface groups by running the following command:

set ip:ip_enable_group_ifs=0

Whenever you modify the /etc/system file, you must reboot the system.