Hi,
Take a backup of the vCenter 4.0 DB (no kidding). Then ensure your DB is supported in 5.1: http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.vsphere.upgrade.doc%2FGUID-93612C3C-CE2E-45D3-951A-C0F5313D7E26.html
If your DB isn't supported anymore do an export and import to a supported version. When your vCenter DB isn't running on the vCenter Server you just have to adjust your 64(!)-Bit DSN.
Don't use the automatic install (which installs SSO, vCenter Inventory and vCenter in that order).
- Start the SSO Setup.
- DON'T CHANGE THE TABLE NAMES, just execute the script delivered on the install ISO. You may change the DB name.
- DON'T use: "The following characters are not supported in passwords: semicolon (;), double quotation mark ("), single quotation mark ('), circumflex (^), and backslash (\). Passwords must comply with Windows Group Policy Object (GPO) password policy.". Link: http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.vsphere.install.doc%2FGUID-200B9E03-D46B-44A9-9B0E-4863D067CFFF.html
- The Passwords of your RSA_Admin and RSA_User users obviously must comply with your (MS)-SQL password policies.
Here's a catchya: If the lookup of your AD fails during SSO install, simply add it afterwards. Don't delay that task.
Then install the Inventory Service, you can't do anything wrong with this one.
Then upgrade-install vCenter 5.1 using the DSN if your DB is remote.
Install the Web Client.
Install the new vSphere Client.
Install or upgrade your existing Update Manager installation and database
Depending on the hosts you have: Look for a custom vendor ISO that may include special VIBs for your hardware (10Gbit NICs, etc).
- Import the ISO to UM. Create a baseline in this process.
- Attach the baseline to the Cluster or ESX hosts.
- Scan.
- Remediate one host at at time. Test with one hosts, especially for missing drivers (e.g. you're doing iSCSI on a 10Gbit NIC that hasn't driver support built-in).
vMotion between Clusters and 4.x and 5.x hosts is fully supported. Use it.
svMotion is supported between VMFS-3 and VMFS-5 datastores. Use it.
Don't upgrade your datastores to VMFS-5 until you evicted or upgraded the last 4.x node from the cluster. 4.x hosts can't read VMFS-5. 5.x hosts can read VMFS-3 and VMFS-5. The Blocksize (1-8MB) of VMFS-3 datastores remains the same, even if upgraded. VMFS-3 partitions upgraded to VMFS-5 remain MBR until they breach the 2TB size. Then they become GPT. If you used other block sizes than 1MB in your VMFS-3 datastores consider wiping and re-formatting them with VMFS-5. That's the only way you get to 1MB blocksize.
VMware Tools upgrade to 5.1 doesn't force a reboot if VMware tools are present on the guest.
Consider upgrading your VM hardware to Version 9. Check if there are virtual peripherals or configurations that aren't supported anymore (e.g.: VLANCE vNICs).
Normally, no downtime is required at all. during this process when admission control was turned on for your old cluster.
Hope this helps,
Kind regards,
Frank