Sequence of powering down the servers in a virtual infrastructure during a power maintenance.

Hi

We have NetApp SAN and 3xFujitsu PRIMERGY ESX host servers and Brocade switches and Cisco switches.
and using VMware - vCcenter appliance.

SAN has two power supplies and
node A power supply is connected to UPS-A
node B power supply is connected to UPS-B

Each of Fujitsu PRIMERGY(ESX)servers have 2xPower supplies  
Each of the PRIMERGY ESX server power supply is connected to UPS-A and UPS-B

Core Cisco switches have 2 power supplier and each of the power supply is connected to UPS-A and UPS-B.

Brocade switches (storage switches) have only one power supply each.
Brocade switch –A is connected to UPS –A
Brocade switch –B is connected to UPS –B

The power maintenance is scheduled by local company and we will not have power for 30 minutes. We have APC UPS  and  APC virtual appliance is setup to power down the servers in a power failure situation when the ups running out of the battery, but this has not been tested on a real-time.
I am hoping the servers should run for 30 minutes on the UPS. But if it exceeds this time I want to power off the server’s safety.

On all the 3 ESX servers , can i power off all the guest machines  and then power off the 3 ESX server one by one - to save power .
So that SAN and brocade switches and core keeps running?
Please let me know the sequence of powering off the server.

Any suggestion will be great
Thanks