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- Two (or more) independently working GitLab sites:
- One GitLab site serves as the Geo **primary** site. Use the [GitLab reference architectures documentation](../../reference_architectures/index.md) to set this up. You can use different reference architecture sizes for each Geo site. If you already have a working GitLab instance that is in-use, it can be used as a **primary** site.
- The second GitLab site serves as the Geo **secondary** site. Use the [GitLab reference architectures documentation](../../reference_architectures/index.md) to set this up. It's a good idea to sign in and test it. However, be aware that **all of the data on the secondary are lost** as part of the process of replicating from the **primary** site.
- Ensure the **primary** site has a [GitLab Premium](https://about.gitlab.com/pricing/) license or higher to unlock Geo. You only need one license for all the sites.
- Confirm the [requirements for running Geo](../index.md#requirements-for-running-geo) are met by all sites. For example, sites must use the same GitLab version, and sites must be able to communicate with each other over certain ports.
1. Optional: [Configure Geo secondary proxying](../secondary_proxy/index.md) to use a single, unified URL for all Geo sites. This step is recommended to accelerate most read requests while transparently proxying writes to the primary Geo site.
After installing GitLab on the **secondary** sites and performing the initial configuration, see the [following documentation for post-installation information](../index.md#post-installation-documentation).