veritas: Mult-Link-based IPMP setup with VCS

With Solaris 10 came a nice feature – Multi-Link-based IP Multipathing (IPMP). It determines NIC availability solely on the NIC driver reporting the physical link status – UP or DOWN. Previous versions used “probe-based” IPMP, where connectivity is tested by pinging something on the network from each interface. While probe-based is actually a more thorough test (tests network layer 3 as well as 2), it is much more cumbersome to configure, and you need an extra IP address for each interface for “test” addresses. IMO Multi-Link-based IPMP is sufficient for most applications.
To achieve multi-link-based IPMP, here’s how I’ve configured my MultiNICB resource in this large 10 node clustered environment:

Multi-Link-based IPMP MultiNICB properties

These are the values you must change from the defaults:
UseMpathd: 1
Tells VCS to use mpathd for network link status
MpathCommand: /usr/sbin/in.mpathd
Be sure to create a symbolic link to /usr/lib/inet/in.mpathd -a if the above does not exist. 
ConfigCheck: 1
If you leave this at 1, it will overwrite your /etc/hostname.xxx files with probe-based IPMP configuration, if left at 0 it will not change.
Device: (your IPMP interfaces here)
List of interfaces and there interface aliases.
Tick on per System and add the device and interface alias entry for each IPMP grouped interface from each host in the cluster.
GroupName:
Do not use your IPMP group name here, it’s not needed. VCS is not monitoring the group, mpathd is.