Cisco MDS 9509 upgrade method

[Gary McCready]

We're looking for best practices to upgrade both our Cisco 9509 -based SAN fabrics, going from 2.1.2b to the newly released (9/2007) version 3.2.1.

Our main debate revolves around long do we wait between fabric upgrades - we will do all four switches (in one fabric) over three sites at once (one site is at 3.0.3.) We would then follow with the other fabric. They are linked with FCIP and doing replication with both EVA and EMC DMX arrays.

Depending on who we talk to (both internal and external), we get recommendations of anything between a few hours (testing in-between) to a few weeks (to make sure there are no new bugs out).

Any recommendations/gotchas?