text: If you plan to add a virtual optical level later to take advantage of improved save and restore 
  times or to use the WORM option, you can initially specify 90 days, for example, for the disk 
  pool level, with no other defined storage levels. When a virtual optical level is added later, the 
  archives are moved from the disk pool level to the virtual optical level. With this technique, you 
  must never add an expiration level after the disk pool level because if that level is 
  encountered, the archives are expired. 
  
  In the status report that is created by ASM, you might see messages that indicate that the 
  number of days in the ASP01 disk pool level was exceeded because no level is available after 
  90 days in this example. You can ignore these messages. 
  
  If you choose the default in the application group to migrate data from cache when data is 
  loaded, a copy of the data is archived to the integrated file system (IFS) CACHE directory and 
  to the ASMREQUEST directory. When you run Disk Storage Manager, the data is deleted 
  from cache after the Cache Data for Days duration ends. When you run ASM for the first time 
  after you load data, the data is moved to the first level of the migration policy, ASP01 in our 
  example. If aggregation is used, the data is not migrated until the appropriate object size is 
  aggregated, or until the number of days to aggregate was passed. The data remains in 
  ASP01 until the number of days in the Life of Data and Indexes is reached or an expiration 
  level in the migration policy is encountered, whichever comes first. 