What is the switchover/failover command I would use if I need to switch/fail over to another chasis? And what are the requirements in order to do such?
Both switches are configured as L2 devices, if that helps. Is it possible in this scenario?
There is an HP Blade that is connected to both (or will be) and there is an uplink connected to the only running switch at this time. All switching is VLAN determined.
Okay you should definitely do this out of hours. You would need to connect a new uplink to the new switch and obviously interconnect the 6500 pair of switches.
If you then wanted to take the old switch out of the equation while upgrading it simply shutdown the uplink and HP blade port. Traffic will then go via the new 6500 and when you have finished upgrading the old switch active the uplink and HP blade ports again.
All of this will cause outages ie.
1) adding the new switch could cause an outage because STP will need to reconverge
2) If you manipulate the STP costs so that after you have added the new switch all traffic is going via the new switch then you can work on the old switch with no downtime but obviously when you bring it back online STP kicks in again.
I'm not talking about huge outages, 50 seconds + with standard STP, a lot faster if using Rapid STP but you will drop packets so that's why it's better to schedule downtime.