vSphere 5 Storage DRS based on Datastore Capacity Utilization
Storage DRS (vSphere 5) introduces the ability to perform automated balancing of storage utilization. SDRS can be performed on a basis of space utilization and also on the basis of I/O load balancing. SDRS allows the aggregation of multiple datastores into a single object called a datastore cluster. SDRS will make recommendations to balance virtual machines or disks based on I/O and space utilization and during virtual machine or virtual disk provisioning make recommendations for placement. SDRS can be set in fully automated or manual mode.