You should name resource pools according to the characteristics of the storage each resource pool contains.
However, for readability, it is advised that names be no longer than 25 characters. You can use any combination of letters, numbers, or special characters in resource pool names.
A label should only be used when you want to more narrowly control the resources being provisioned. For example, if you want to restrict the provisioned resources by their cost and performance, you might assign a label of Tier-1, Tier-2, or Tier-3. If a Tier-1 resource label is selected for a provisioning policy and a provisioning action occurs, only those resources assigned to the dataset and labeled as Tier-1 is considered for provisioning.