Can anybody tell me what the advantage is of using a template, vs installing EM with an empty database. The latter will also populate the database. So why preconfigure the repository if it is done by the the OMS installation?
this template is available on http://www.oracle.com/technetwork/oem/enterprise-manager/downloads/index.html
Preconfiguring the repository in the database can help save time/speed up EM deployment in some cases. For example, while you are waiting for a machine to be acquired and prepared for EM installation (i.e., the installation of the first OMS), you can preconfigure the database (on a separate machine). Once the (OMS) machine is ready, it will be faster to complete the EM installation as the repository has been already configured.
so much for the seed database which Oracle provided for 188.8.131.52 em 12c.
When installiing OMS, the seed database redo logs where too small, the processes was 300 instead of 600, and the shared_pool_size was too small. Al things needed to be in the seed db BEFORE you start.