I need to migrate from ePO 4.0 to ePO 4.5, yet the scenario I describe my architecture.
I have a ePO 4.0 console with agnte 4.0 with SQL database in 2000, the database migration weighs 3Gb and I have to do the same in production server environments do not have proof.
I can support this report provides best practices for migration to 4.5 and Agent 4.5.
Honesty, this is best covered in the ePO 4.5 Installation guide.
The Installation guide is searchable in the Knowledge base, which is linked here:
Primary consideration for you though should be that ePO 4.5 requires Sql2005 as a minimum.
You will be looking at an Sql Server upgrade as well as DB migration.