You must determine how many repositories are needed in your environment and where to locate them.
To answer these questions, you must look at your ePO - On-prem server managed systems and your network geography.
Consider the following factors:
How many nodes do you manage with the ePO - On-prem server?
Are these nodes located in different geographic locations?
What connectivity do you have to your repositories?
Remember, the purpose of a repository is to allow clients to download the large amount of data in software updates locally instead of connecting to the ePO - On-prem server and downloading the updates across the slower WAN links. At a minimum, your repository is used to update your signature, or DAT files for Threat Prevention daily. In addition, your repository is used by your agents to download new software, product patches, and other content, for example Host Intrusion Prevention content.
Typically you can create a repository for each large geographic location, but there are several caveats. Plus, you must avoid the most common mistakes of having too many or too few repositories and overloading your network bandwidth.