SharePoint 2013 multi server farm Standard to Enterprise version upgrade error and resolution

It is always easy to upgrade standalone farm rather than multi server farm. If you look MSDN, the article says enter enterprise key and upgrade and you get success message. It is true for few scenarios. But most of the time we get failure message like

"The upgrade is failed...xxx.. check event log". In my case, when I check event log, I could able to see many errors not related to upgrade. After trying all ways finally I decided to do upgrade using PowerShell command PSCONFIG.Exe -cmd.

https://technet.microsoft.com/en-us/library/cc263093(v=office.14).aspx 

Please follow below steps for multi-server farm 

1. Stop 'SharePoint Timer Service' in all servers except, server (s) hosting central administration site. 

2. Login to server, where central admin hosted 

3. Go to central admin and start upgrade. Surely, you will get error. But when you check event log, you can observe the success message, which means upgrade completed successfully. But it’s throwing error, which means, other servers in the farm not upgraded successfully.

4. Login to each server (web & app) in the farm, except the server which is hosting a central admin.

5. Run following command in SharePoint 2013 management shell (always run as administrator)

            Psconfig.exe –cmd services –install

    

6. upon success, run following command

            Psconfig.exe –cmd installfeatures

   

7. Run following command in SharePoint 2013 management shell - in central admin hosted servers

            set-spfarmconfig -installedproductsrefresh

That’s it!... go back to central admin and check the upgrade status…. You can see that, your farm has been upgraded to enterprise…