Dell UnityOS version 4.2 introduced dynamic pool technology for Dell Unity all-flash storage systems. In UnityOS version 5.2 support for dynamic pools on hybrid model systems was added. This is the default pool type when creating pools in Unisphere. This new pool technology is designed from the ground up, with a new method for allocating space within the pool than traditional pools. This design allows for flexible deployment options, and allows users to design or expand dynamic pools with a specific capacity in mind. The pool sizing requirements are based on minimum drive counts, and not drive multiples. As long as the minimum drive counts are met, the pool can be any number of drives, and can also be expanded by a single drive in most circumstances to increase the capacity of the pool.
With dynamic pools, no hot spares for failed drive replacement are required, since all space for drive rebuilds is allocated within the pool. Drives which would be reserved as hot spares for traditional pools are incorporated into the pool to further spread out user space and space to use for drive rebuilds. As drives within dynamic pools are partitioned into extents, the pool can easily move data around to balance workloads when the pool is expanded. If a drive fails, multiple extents can be rebuilt at the same time, and to multiple drives within the pool. This further reduces the amount of time a rebuild of a drive takes when compared to a rebuild within a traditional pool.
Dynamic pools are also designed to help mitigate flash wear. Since drives previously reserved as Hot Spares are now incorporated into the pool, the user data and workloads are spread out across more drives. This reduces the amount of wear per drive within the pool. Also, wear is further monitored within a dynamic pool, and if needed, data can be moved between drive partnership groups to further spread out wear. This is an automated process that requires no intervention by the user.