Azure Cosmos DB automatically scales available storage as the size of your data set increases. There is no practical limit to the amount of storage that can be used in a Cosmos DB database or collection. Blue Matador monitors the amount of available storage using the AvailableStorage metric in Cosmos DB Accounts and will alert when the remaining storage is low. Since Azure automatically provisions more storage, this case should be exceedingly rare but may occur in the event of a very large ingestion of data. Running out of storage will cause requests to fail until more storage is provisioned. If this ever occurs, contact Azure Support to try and get the storage amount increased to the necessary amount.