If the storage limit that's associated with the maximum throughput of the database or container is exceeded, Azure Cosmos DB automatically increases the maximum throughput to the next highest RU/s that can support that level of storage.
For an example scenario, if you start with a maximum RU/s of 50,000 RU/s (scales between 5,000 RU/s and 50,000 RU/s), you can store up to 5,000 GB of data. If your storage size increases to 5,001 GB, storage is now 6,000 GB and the new maximum RU/s is 60,000 RU/s (scales between 6,000 RU/s and 60,000 RU/s).