A system experiencing a problem using one or more RACF® cache structures might enter read-only mode, with RACF issuing message IRRX004A. With the exception of statistics updates during logon and job initiation, and other statistics updates made with ICHEINTY ALTERI requests, the RACF manager rejects requests to update the RACF database with return code X'50'. This might cause occurrences of abends 483-50 or 485-50.

It is important to note that error messages resulting from read-only mode indicate a coupling facility problem, and not a problem with the RACF database. Along with message IRRX004A, RACF issues one or more additional diagnostic messages to assist in correcting the problems with the coupling facility.

Because serialization for read-only mode is compatible with serialization for data sharing mode, other systems in the sysplex can continue using the coupling facility while the operator corrects the problem on the read-only system.

While in read-only mode, RACF listens for ENF signals indicating any changes in coupling facility availability and automatically tries to connect and enter data sharing mode when it receives an ENF signal that indicates that RACF-related resources are available. This might result in repeated IXLCONN failures due to unrelated coupling facility changes. For this reason, RACF does not issue error message IRRX003A when the connect attempt is due to an ENF signal. MVS™ does, however, log every IXLCONN failure in SYS1.LOGREC, so that if multiple errors occur diagnostics are available.