2.7.5 IMS Structures and Volatility
The IRLM lock structure for IMS locks should be allocated in a nonvolatile CF.
Recovery after a power failure is faster if the locks are still available.
IMS issues a warning message if the lock structure is allocated in a volatile CF.
The message is also issued if the volatility of the CF changes. No attempt is
made to move the structure should the volatility change.
The cache structures for VSAM, OSAM, and VSO DEDBs can be allocated in a
nonvolatile or volatile CF.
The IMS CQS list structures can be allocated in a volatile CF; however, to
minimize recovery time following a power failure, we recommend placing the
CQS structures in a nonvolatile CF. CQS will issue a message if the CF changes
state from nonvolatile to volatile. IMS does not attempt to move any of the
structures should the CF become volatile.
Chapter 2. A Structured View of CF Structures