Changing the size of OSAM and VSAM structures
You can dynamically change the size of OSAM and VSAM cache structures or reapportion objects within a structure by using Structure Alter.
You can also automatically perform Structure Alter when a structure fills to change the structure size and element-to-entry ratio. A coupling facility level of 1 is required to support Structure Alter.
For more information about Structure Alter, see Using structure alter for CQS.