You will find these storage types in connection to Cloud Backup for Veeam.
Permanent storage is what you contractually request (1 TB/month minimum). It is always at your disposal and it cannot be modified as swiftly as Burst storage. (Permanent storage is associated to a contractual obligation.)
This type of storage can be added swiftly and removed on demand. For an additional charge, it can be acquired on a monthly basis making it the best solution when you need more backup storage as quickly as possible.