A storage system comprises a plurality of storage devices, and is configured to establish a production drive group comprising a first subset of the storage devices, using a first firmware-level configuration process, and to establish a stealth drive group comprising a second subset of the storage devices, using a second firmware-level configuration process, the storage devices of the stealth drive group thereby being separated at a firmware level of the storage system from the storage devices of the production drive group. The storage system is further configured to copy data of one or more logical storage volumes from the production drive group to the stealth drive group, and responsive to completion of the copying of the data of the one or more logical storage volumes from the production drive group to the stealth drive group, to initiate a firmware-level reconfiguration process for the storage devices of the stealth drive group.