Hi,
I don't know if you still need more info but I thought I would Chime in as I recently switched from IPMP over to Link-aggr and LACP.
What we found is due the application we were using, Load spreading was not working as expected.
IPMP is supposed to load balance only outbound traffic based on my research. What I found when reviewing dlstats, were only one port was actually being used.
- Due to this our application was impacted. Users reported slow connectivity during peek times. We took a look at the server and there were plenty resources available since this is a new implementation and only one application on the server at the time. The application is network heavy. (IPMP configuration is what was recommended to us. There is a possibility that when it was setup, it was not done correctly).
As Solaris was pretty new to me and I came into the project half way, I suggested switching over to using link aggregation instead. Once switched over, performance has improved from the user experience which was the goal.
Not sure if this helps.
(I'm not a solaris admin but was only helping out to troubleshoot the issues)