You can specify whether you want the system to automatically alter a structure when it reaches an installation-defined or defaulted-to percent full threshold as determined by structure full monitoring. The alter process may increase the size of the structure, reapportion the objects within the structure, or both. For a structure to be eligible to automatically be altered the following is assumed:

• The application connecting to the structure has specified that alter is allowed by specifying AllowAlter=YES on one or more of the IXLCONN invocations.
• The installation has specified that system-initiated alter of the structure is allowed (ALLOWAUTOALT(YES) in the active CFRM policy) and is being monitored by the structure full monitoring function.
• The structure is not in the process of being rebuilt. A structure that is in the process of being rebuilt, either as a result of user-managed or system-managed rebuild, is not eligible to be altered automatically. The exception to this rule is for structures in a user-managed duplexing rebuild environment and structures in the duplex established phase.
• The SETXCF MODIFY command was NOT used to disablealter for the structure. Starting CF structure alter processing for such structures is not permitted.