A query-based spares management technique enables a storage operating system of a storage system to select disks to be added to one or more RAID groups of a volume. The spares management technique includes an attributes-based disk selection procedure that is performed by the storage operating system in response to an operator-initiated request to add disks to the volume or in response to a demand-driven request resulting from a requirement imposed by the system to add disks to the volume. The disks that are added to the RAID groups of the volume are retrieved from one or more spare pools of disks maintained by the storage system.