VMware vCenter 4.0 - 4.1 Migration with OS Reinstall

In order to move our infrastructure to VMware ESX/ESXi 4.1, I needed to upgrade our vCenter 4.0 install to 4.1 which now requires a 64 bit OS. I performed the reinstall from Windows Server 2003 SP2 Std. to Windows Server 2003 x64 with SP2 using the same HP DL360 G5 chassis as I didn't have any spare hardware at the time. In order to give myself a roll-back strategy I popped the original disks and installed Windows and vCenter on a new pair of 146GB 15k SAS disks.

The upgrade of vCenter from one machine to another is recognised process in the vCenter 4.1 upgrade guide (here) and therefore I didn't see a reason why it couldn't be performed but using the same hardware and difference disks, so I planned my approach based on it and I've listed my steps below.


Preparation

• Complete vCenter Installation Worksheet as supplied by VMware
• Document "Server Name" Network Configuration
• Acquire vCenter 4.1 Install Media
• Back Up VirtualCenter or vCenter Server Configuration with the Data Migration Tool (Page 40 vSphere 4.1 Upgrade Guide)
• Copy datamigration folder from "Server Name" to "Network Location"
• Copy legacy licenses from "D:\Program Files\VMware\VMware License Server\Licenses" to "Network Location"
• Power Down "Server Name"
• Remove Current Disks holding "Server Name" config and store
• Backup VC Database on "Database Server Name"
• Grant DBO on MSDB and VC Databases

Server Rebuild

• Insert new disks into "Server Name" chassis
• Build server using Windows 2003 Enterprise x64 SP2
• Configure Network and test
• Join to Domain

Install vCenter 4.1

• Copy datamigration folder from "Network Location" to "Server Name"
• Download and Install 64-bit SQL Native Client from Microsoft 
• Create a 64-Bit DSN (page 40 of vSphere 4.1 Upgrade Guide)
• Restore the vCenter Server Configuration and Install vCenter Server on the Destination Machine (page 41 of vSphere 4.1 Upgrade Guide)
• Follow the install prompts for vCenter install
• Verify install was successful
• Install VMware License Server
• Copy Licenses from "Network Location" to "D:\Program Files\VMware\VMware License Server\Licenses"
• Reload the licenses into "Server Name"

Post Install Checks

•  Open vCenter and check that the new vCenter agent is being deployed to the ESX/ESXi hosts (the tasks may not appear immediately)
• Remove DBO for the SQL user on the MSDB SQL Database

  Note: If you intend to deploy pre Windows Server 2008 operating systems (2000, XP and 2003), the Sysprep tools require installing back to the vCenter server. Details can be found here