Upgrade on a Distributed Environment

I am upgrading my ERP system from Ehp4 to Ehp6. I have a distributed environment consisting of a CI server (1 CPU & Fault Tolerant), a Database server (6 CPUs), and 4 application servers (each 2 CPUs) , 2 of which are dedicated to dialog and 2 dedicated to background jobs. I getting an error in the upgrade prep because background job RDDIT008 cannot write to the upgrade directory which is on the CI server. So my question is how do I run an upgrade on such a distributed environment? Since my servers are VM I do have some flexibility in hardware configuration.