Storage distributed resource scheduler (SDRS) has been introduced in vSphere 5. More details about its features and usage can be found in the Balancing loads between datastores recipe in this chapter.

SDRS load balancing constantly monitors datastore space utilization and I/O latency. When one of the configured thresholds for these metrics is exceeded on a particular datastore, SDRS calculates the possible options for VM storage migrations and recommends the one that offers the best load distribution.