A storage pool is a collection of SSDs. You can combine SSDs to create a storage pool, which enables you to share the SSDs and SSD spares across multiple Flash Pool aggregates, at the same time.
Storage pools consist of allocation units, which you can use to provide SSDs and SSD spares to aggregates or to increase the existing SSD size.
After you add an SSD to a storage pool, you can no longer use the SSD as an individual disk. You must use the storage pool to assign or allocate the storage provided by the SSD.