Automatic versus manual pool creation
You create pools automatically or manually to allow physical storage to be grouped, and then dynamically allocated as needed. When a pool is created, you can add physical drives.
Automatic pool creation is initiated when System Manager detects unassigned capacity in a storage array. When unassigned capacity is detected, System Manager automatically prompts you to create one or more pools, or add the unassigned capacity to an existing pool, or both.
Automatic pool creation occurs when one of these conditions is true:
Pools do not exist in the storage array, and there are enough similar drives to create a new pool.
New drives are added to a storage array that has at least one pool.
Each drive in a pool must be of the same drive type (HDD or SSD) and have similar capacity. System Manager will prompt you to complete the following tasks:
Create a single pool if there are a sufficient number of drives of those types.
Create multiple pools if the unassigned capacity consists of different drive types.
Add the drives to the existing pool if a pool is already defined in the storage array, and add new drives of the same drive type to the pool.
Add the drives of the same drive type to the existing pool, and use the other drive types to create different pools if the new drives are of different drive types.
You might want to create a pool manually when automatic creation cannot determine the best configuration. This situation can occur for one of the following reasons:
The new drives could potentially be added to more than one pool.
One or more of the new pool candidates can use shelf loss protection or drawer loss protection.
One or more of the current pool candidates cannot maintain their shelf loss protection or drawer loss protection status.
You might also want to create a pool manually if you have multiple applications on your storage array and do not want them competing for the same drive resources. In this case, you might consider manually creating a smaller pool for one or more of the applications. You can assign just one or two volumes instead of assigning the workload to a large pool that has many volumes across which to distribute the data. Manually creating a separate pool that is dedicated to the workload of a specific application can allow storage array operations to perform more rapidly, with less contention.