I am in the process of upgrading my ACS deployment from 5.2 to 5.3.  When I first got to this company we had one 3.x ACS Appliance that was woefully unsupported and out of date.  Since I started I managed to purchase two vmware servers with the large deployment license.  So my configuration is this:

Primary Server + Log Collector at the main site

Secondary Server at our remote site

As I read through the documentation for the upgrade and tried to understand Cisco’s convoluted process of actually upgrading stuff, I came to a stark realization.  The DB from 5.2 can be directly imported into 5.3….

I quickly ditched all plans I had to follow Cisco’s cruddy upgrade process and just made sure all of my equipment had both the primary and secondary ACS servers setup.  I then created a brand new 5.3 server and performed all of the necessary patches to get it to the latest and greatest.  After that I exported my 5.2 database then imported it into 5.3.  Once I had done some testing and was sure my new 5.3 was good I then shutdown the 5.2 Primary and swapped the ip to the new Primary 5.3.  I then did the same process for my secondary and then restarted the distributed database.

Much easier upgrade and didn’t require more than 5 minutes of downtime and since I had two ACS’s nothing was missed during the time and no one was denied access to the network.

Thanks Cisco for making at least one thing in life easy and keeping the databases compatible.