Customers of shared resources in a multi-tenant environment can modify operational parameters of electronic resources. A customer can be provisioned a data volume of a specified size, storage type (e.g., hard disk drive or solid state device), committed rate of input/output operations per second, and/or geographical location, for example. The customer can subsequently modify any such operational parameters by submitting an appropriate request, or the operational parameters can be adjusted automatically based on any of a number of criteria. Data volumes for the customer can be migrated, split, or combined in order to provide the shared resources in accordance with the modified operational parameters.