When you start a trial in Gearset you have the option to choose the data storage location of your Gearset app, depending on your needs.
If you choose the US, Australia or Canada the data center, your app will show you the data storage location.
US example:
Australian example:
Canada example:
If there is no data storage location displayed, then by default your data location is the EU.
The Gearset EU data center is located in Ireland. More specifically, the AWS data center handling the EU region for Gearset is in Dublin.