Disabling 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 software, but as optional behavior in subsequent releases.

As described in the ifconfig(1M) man page, logical or physical interfaces that share an IP prefix are collected into an interface group. IP uses the interface group to rotate source address selections when the source address is unspecified. An interface group made up of multiple physical interfaces is used to distribute traffic across different IP addresses on a per-IP-destination basis (see netstat(1M) for information about per-IP-destination).

When enabled, the interface groups 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. Therefore, interface groups must 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 editing the /etc/system file to include the following line

set ip:ip_enable_group_ifs=0

Whenever you modify the /etc/system file, you must reboot the system for the changes to take effect.