Checklist for upgrading VM hardware

When upgrading a VMware Virtual Infrastructure 3.5 cluster to a vSphere 4.0 cluster, at some point after the upgrade you will have to upgrade the virtual machines from version 4 to version 7 machines. This process is relatively easy but the steps must be followed in order for it to work successfully.

First the operating system needs to be identified. If the operating system is Windows Server 2008 Enterprise or Datacenter editions there is a known bug. This issue is due to the operating systems default SAN policy, which will cause additional virtual disks to go offline during the upgrade process which could drive you crazy if it is a Domain Controller, SQL server or Exchange server.

To fix this issue, you must use the diskpart utility to adjust the SAN policy with the following steps:

1. Log on to the system with administrative rights.

2. Click Start, click Run, type cmd, and then press ENTER.

3. In the command line window, type diskpart, and then press ENTER.

4. Type SAN, and then press ENTER. This command will return the current set SAN policy.

5.Type SAN POLICY = Online, and then press ENTER. The SAN policy is now set not to automatically mount SAN hosted volumes.

6. Type exit, and then press ENTER.

The next step in the process is to verify that we are at Version 4 and that the latest VM Tools is installed on the virtual machine. This can be verified in vCenter by selecting the virtual machine and looking at the summary tab, it will list the VM version and it will also tell you if VM tools is installed, out of date or OK.

Provided the latest VM tools are installed we can now upgrade the hardware. Warning, this upgrade process is a one-way upgrade, there is no reversal. A snapshot is not going to work to rollback the upgrade if something goes wrong. If the data is that important a back up should be created either by exporting the VM someplace safe or by creating a clone, before you start the upgrade process.

Shutdown and power off the virtual machine, the upgrade cannot happen while it is on or suspended.

From the vCenter console right-click on the virtual machine. From the context menu, you should see an option enabled called “Upgrade Virtual Hardware”, click on this with the mouse.

You will be prompted if you want to proceed with the upgrade click the “Yes” button to proceed.

Startup up the virtual machine. After a few minutes the server will need to be rebooted as the Windows operating system should detect all the changes and add the new drivers. Reboot the server and your upgrade is complete.