Guarding against data corruption resulting from incorrect database sharing when changing the status of a RACF database

When issuing the RVARY command on a z/OS® V1R10 or higher system to activate a database (by specifying the ACTIVE parameter), or to enter data sharing mode (by specifying the DATASHARE parameter), the RVARY command will locate all IRRPLEX_sysplex-name profiles in the GXFACILI class to determine how the database has been accessed previously. The RVARY command checks the IRRPLEX_sysplex-name profiles in the database, because it could be a different database than the one checked at IPL-time. If the RVARY ACTIVE command is issued and the information provided by the IRRPLEX_sysplex-name profiles indicates that activating the database might risk data corruption, a WTOR message will be sent to the system console. For example:

Table 1. Potential data corruption messages displayed when issuing the RVARY ACTIVE command
If issuing the RVARY ACTIVE command to:	And the RVARY command finds:	Then a WTOR message will be sent to the system console to inform the system operator that:	The system operator can choose to:
Activate a database in non-data sharing mode	Any IRRPLEX_sysplex-name profile whose APPLDATA field indicates "DATA SHARING MODE"	A profile indicates the database was last used in data sharing mode, and database corruption will result if it is currently being used in data sharing mode and this system accesses it in non-data sharing mode.	Continue the operation, if he or she is certain the database is not being used by another system in data sharing mode. If the database is being used by a sysplex in data sharing mode, cancel the operation.
Activate a database in data sharing mode	Any IRRPLEX_sysplex-name profile besides the one for the sysplex.	A profile besides the one for the current sysplex was found, indicating that another sysplex might be using the database. If so, accessing the database in data sharing mode might result in database corruption.	Continue the operation, if he or she is certain the database is not being used by another sysplex. If another sysplex is using the database, cancel the operation.
Activate a database in data sharing mode	No IRRPLEX_sysplex-name profiles except the one for the current sysplex, and the APPLDATA field of the profile indicates "NON-DATA SHARING MODE"	A profile indicates the database was last accessed by the sysplex in non-data sharing mode. The sysplex is about to start accessing the database in data sharing mode.	Continue the operation, if he or she is certain the database is not being used by any system outside the sysplex. If the database is being used by any system outside the sysplex, cancel the operation.

If the RVARY DATASHARE command is issued and the information provided by the IRRPLEX_sysplex-name profiles indicates that entering data sharing mode might risk data corruption, a WTO message will be sent to the system console and the RVARY DATASHARE will be cancelled. Specifically, if issuing the RVARY DATASHARE command to enter data sharing mode, and the RVARY command finds any IRRPLEX_sysplex-name profile besides the one for the sysplex, then a WTO message will be sent to the system console. This WTO message will inform the system operator that a profile besides the one for the current sysplex was found, indicating that another sysplex might be using the database. If so, accessing the database in data sharing mode might result in database corruption. For this reason, the command does not complete successfully. After the system cancels the RVARY DATASHARE to avoid database corruption, you can check the profiles to determine if they accurately reflect the way the database is being accessed.

If the profiles are correct, do not attempt to enter data sharing mode.
If the profiles are extraneous and do not reflect the actual database usage, you can RDELETE them and reissue the RVARY DATASHARE command.

If the RVARY command does change the mode, it will also update the APPLDATA field of the sysplex's IRRPLEX_sysplex-name profile to reflect the new mode.

Note: Keep in mind that the RVARY command performs these additional database-protection checks only if the command is issued on a z/OS V1R10 or higher system. If you have a sysplex that combines systems running V1R10 or higher with systems running V1R9 or lower, you should issue the RVARY command from a V1R10 or higher system. If issued from a V1R9 or lower system in the sysplex, the RVARY command will not perform any database-protection checks.

Also be aware that, when issuing the RVARY command on a z/OS V1R10 or higher system to begin data sharing mode (by specifying the DATASHARE parameter) or non-data sharing mode (by specifying the NODATASHARE parameter), the RVARY command will update the APPLDATA field of the sysplex's IRRPLEX_sysplex-name profile to reflect the new mode. For this reason, you should also issue any RVARY DATASHARE or RVARY NODATASHARE command from a V1R10 or higher system. If issued from a V1R9 or lower system, the RVARY command will not update the APPLDATA field of the sysplex's IRRPLEX_sysplex-name profile to reflect the new mode. Because the APPLDATA field will no longer reflect the last mode the sysplex used to access the database, this will compromise the capability and reliability of the checks that are performed by the V1R10 systems in the sysplex.

The warnings about possible data corruption generated by the RVARY command are, like the warnings generated at IPL-time, only as reliable as the information provided in the IRRPLEX_sysplex-name profiles in the GXFACILI class.

Guarding against data corruption resulting from incorrect database sharing at IPL time contains information on how you can improve the system's ability to detect incorrect database sharing by creating one or more IRRPLEX_sysplex-name profiles in the GXFACILI class to fully describe how the RACF® database is being accessed. You should take these actions before you IPL the R1V10 or higher system to improve the reliability of the checks performed at IPL-time. If, however, you did not take these actions prior to IPLing the system, you can still take them after the IPL to improve the reliability of the checks performed by the RVARY command.