text: **Cache-only storage:**If the storage set contains cache-only storage nodes, ensure that 
  the Cache Data value and the Life of Data and Indexes value are the same. Otherwise, the 
  add or update operation cannot be completed. 
  
  **Scenario 2: Cache, then migration to storage, and then expiration**
  In this scenario, the storage object is first stored to cache for a short period, after which it is 
  migrated to a storage manager for long-term storage. 