The batch size setting on the Data management page is how you can control the batch size of a data deployment when transferring data from a source org to a target org. This is a setting team owners can access.
The batch size controls the number of records in each set of data that Gearset sends to Salesforce during a data deployment. The default batch size is 10000.
A large batch size means you'll have more records in each batch, and so fewer batches overall. Fewer batches result in faster data deployments.
A large batch size can sometimes cause Apex timeouts for triggers that run when data is inserted or updated. If you're experiencing timeouts from triggers during a data deployment, try reducing the batch size.