How much do you have in terms of custom rules/config, add-on products, extensions etc?
I would start by building the new 5.1 ePO. Then somewhere along the lines of:
- add the security keys from the 4 other ePO's into the new
- add the seucrity key from the new in the old
- make sure port traffic comm is open between old/new server
- register the new ePO in all the old ePO's
- export all your client tasks/server tasks/policies/queries/tree/tags/etc. and import them into the new
- Assign policies into new tree
- Starting moving agents from old ePO's to new
There is more to it then that, and that's not the only way of doing it, but something you could do.
Remember, the Agent uses either the last known IP address, DNS name, or NetBIOS name of the ePO server. If you change any one of these, ensure that the Agents have a way to locate the server. The easiest way to do transfer machines is to retain the existing DNS record of the old ePOs and change it to point to the new IP address of the new ePO server. After the Agent is able to successfully connect to the new ePO server, it downloads an updated SiteList.xml with the current information.
how shall I set the new infrastructure ? 1 server managment (policy and DB ) and 4 servers located in different sites ?
It really depends on the amount of endpoints at your 4 sites, network speed & your environment in general. You might be able to just use 1 ePO (policy/db) and then 4 SADRs, 1 at each site. Otherise you could use AH's at the 4 sites, just depends on your environment.