DELL PDF document about dynamic pools: h16289-dell_emc_unity-dynamic_pools.pdf Page 20-21. The smallest RAID 5 stripe width the system supports is a 4+1. The smallest dynamic pool created with the RAID 5 4+1 configuration is 6 drives. The minimum drive count includes the number of drives specified in the stripe width, plus the hot spare capacity. The hot spare capacity is selected by the user at pool creation, and can either be set to 1 or 2 drives for every 32 drives in the pool.