While working on a vSphere upgrade project for a very large install base , I faced the issue with the vCenter upgrade failing from vCenter 4.x to vCenter5 with a wrong JDBC URL failed message. This type of issue is already described in KB articles from VMware.
http://kb.vmware.com/kb/2006642
http://kb.vmware.com/kb/2007301
wrong URL format for the JDBC reported by the vCenter Installer , . There is also a reference of JDBC URL Formats for the vCenter Server Databaseas how it should be entered.
The challenge that we faced was to figure out what is the correct database used for the vCenter , to find out what is the correct database name used by the vCenter so that you can complete the correct JDBC URL. we followed the steps below.
Login to the machine where you have the vCenter database installed , open the SQL Server Configuration Manager , note down the Process ID in front of the DB instance name , under the SQL Server services option. For example here it is 1524.
Now open the Windows task manager go to services and match the process ID with the one in the task manager , this will be your database instance name used by the vCenter. In the example below it is SQLvm.
You need to use this as the Database instance name in the vCenter Installer screen as per the JDBC URL Formats for the vCenter Server Database . Once done click next and you should proceed with the installation.