if you are running an All-In-One device you have to migrate the ELM Management DB before adding any storage pools.
You need to migrate your management database off of the ELM. Make sure that you do not migrate it to the same storage pool as your ELM logs. I am sorting out an ugly situation now because I made that mistake. Make sure that you have two separate storage pools: one for your management db and one for your ELM logs. Once you have the dedicated storage pool for the management db, you can migrate it from the ELM properties page. Go to "ELM Configuration" and click on the "Migrate DB" button. Then just pick the storage pool that you want.
That's correct esher72.
But just to clarify your response - based on my testing, management database can only be migrated to "Storage device" not "storage pool".
So based on the recommendation, there needs to be at least two "storage devices" - one for management database (min size 500gb) and one or more for ELM log retention.
Once the storage device is set for mgmt db, you can migrate db from ELM properties.
Storage pools can be defined from the second storage device for log retention.