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Is there a lot of other traffic on the 5548s and 6224s? You may want to try the lacp timeout short command on the 6224 and the 5548s and see if that helps. Is the VLT interconnect a static LAG? Have you tried making the LAG from the Powerconnects to the Force10 a static LAG? Is the firmware on each device up to date? Page 974 shows some other things to check for the recommended configuration. http://www.force10networks.com/CSPortal20/KnowledgeBase/DOCUMENTATION/CLIConfig/FTOS/S4820T_9.4(0.0)...
Currently there is nearly no traffic as this is a lab environment we are testing in before going to production. LACP is indeed set to short timeouts. Let me try a static LAG, though that seems counterintuitive when it comes to resiliency.
For the static lag it is just to test to see if it is an LACP issue causing the delay.
We figured it out. It turns out it was the Hello Time in RSTP. One of the Force10 white papers describes setting the Hello Time to .5 sec which we did. It turns out that is bad. The PowerConnects were at a Hello Time of 2 (the protocol default) and could not be set as low as 0.5. Once we set the Force10s to a Hello Time of 2, the world was happy. 700ms failovers were had by all.