Log stream staging data sets can aid an installation in providing disaster recovery opportunities for the log data written to log stream primary storage. When the primary and secondary site sysplex system(s) were appropriately configured, the installation would need to take the necessary actions at the recovery site. When XRC is used to mirror DASD volumes, XRC XEND (possibly XSUSPEND) and XRECOVER command(s) would be issued at the recovery site to reestablish the appropriate consistency of the resources for the volumes in the XRC (logical) session(s). See Plan DRXRC-type staging data sets for coupling facility log streams earlier in this chapter for more details on establishing the appropriate environment for this duplexing approach.

1. When the first recovery system at the secondary recovery site is initially being IPLed as part of a disaster recovery scenario and special handling of certain resources are required, the DRMODE=YES IPL option should be specified. For these specific IPLs,
   • the systems programmer must ensure the XRC DefaultSessionId and DefaultHlq values are set accordingly on the CONTIME specification in the ANTXINxx parmlib member in SYS1.PARMLIB, and
   • Logger will issue decision message IXG068D and wait for a reply.
2. A DISPLAY LOGGER,STATUS command will result in an IXG601I message indicating the system logger status. When a system is IPLed with the DRMODE=YES specification and the IXGLOGR address space is started, this display command will result in an IXG601I message with a system logger status of one of the following:
   • INITIALIZING - DRXRC CONVERSION NOT DONE
   • ACTIVE - DRXRC CONVERSION NOT DONE

   The INITIALIZING text in the status may appear before Logger issues message IXG068D. Once the status has the ACTIVE text, before responding to message IXG068D, enter a DISPLAY LOGGER,L,LSN=* command and view the resulting IXG601I message to identify the log streams that have STAGING DRXRC included as a duplexing method. These log streams, with duplexing method STAGING DRXRC, will be affected by the response to the IXG068D message.

3. A reply of Y to message IXG068D will cause Logger to issue message IXG072I indicating the DASD consistency time that will be used for log data.

   If Logger encounters errors while attempting to obtain the DASD consistency time from XRC, messages IXG070I and IXG071D will be issued to identify the error and requesting a response on how to continue. The options are for Logger to retry to obtain the consistency time from XRC after the installation took steps to remedy the reason for the failure identified in message IXG070I. The other option is to request that Logger use the current time as the consistency time and all the log data in the converted DRXRC-type staging data set resources will be used during log stream log data recovery. This means that some log data will be more recent or up to date, so there will not be any missing log data; however, some log data, in the converted DRXRC-type staging data sets, might not be time consistent with the rest of the Logger configuration.

4. After identifying the log streams that had DRXRC-type staging data sets in use, these log streams will have their attributes updated to the following specification: STG_DUPLEX(NO),DUPLEXMODE(). Message IXG224I is issued, to hardcopy, for each log stream that is updated.

   This attribute change is made since the intent of DRXRC-type staging data sets is to allow the log stream recovery to occur on the secondary (remote) site. Once the log data has been recovered, the installation's need for using DRXRC-type staging data sets has just been satisfied. It is expected that continued use of these recovered log streams on the secondary sysplex (recovery) site should not automatically cause new staging data set duplexing. The installation will have to reestablish any specific duplexing if the automatic log stream duplexing setting are not desired.

5. If Logger is unable to complete the conversion of all log streams that had DRXRC-type staging data sets in use before the IPL of this recovery system, message IXG073D will be issued requesting a response on how to continue. The options are to retry the process of converting, identifying and preparing, any remaining log stream DRXRC-type resources for log data recovery use.

   The other option is to request that Logger cancel the DRXRC-type conversion process and complete Logger initialization. With this option, log streams that have DRXRC-type staging data sets that are not yet converted, will be treated as if the system were IPLed with DRMODE=NO. If the only copy of these log streams' primary, interim, log data are in DRXRC-type staging data sets, recovery for these log streams will most likely result in being marked damaged (possible loss of data). A DRXRC-type staging data set will only be used for recovery of log data if Logger was able to successfully complete the conversion of the corresponding log streams that had DRXRC-type staging data sets in use.

6. After the appropriate log streams have their DRXRC-type staging data sets marked as eligible to be included for log data recovery, message IXG069I is issued and Logger will perform its system level recovery for log streams that have failed connections for the system being IPLed.
7. If message IXG069I has not been issued and this recovery system needs to be re-IPLed, the DRMODE=YES option needs to be specified again to allow Logger to complete the preparation for converting the DRXRC-type staging data sets for use in log stream log data recovery.
8. Once message IXG069I is issued, all remaining recovery systems can be IPLed with DRMODE=NO and Logger will use the previously defined and converted DRXRC-type staging data sets as part of the system level log stream recovery on those systems as well.

For the above environment, if the appropriate XRC actions are not taken to ensure the Logger configuration on DASD is consistent, unpredictable results can occur for Logger and its exploiters.

When a recovery system is IPLed with DRMODE=NO specified, or defaulted, or if the reply to IXG068D is N, System logger will not include DRXRC-type staging data sets in its log data recovery for coupling facility structure-based log streams that had been connected before this IPL. If the only copies of some log streams' primary (interim) log data are in a DRXRC-type staging data set, the recovery for these log streams might not succeed (message IXG212E) and the log streams marked as damaged (possible loss of data).

Regardless of the DRMODE= specification or the reply to an IXG068D message, Logger's conventional log data recovery processing for log streams continues to be performed as part of system level/connection log stream recovery.

The installation system programmer should consult with the installation storage administrator to determine which recovery function should be used. See Plan DRXRC-type staging data sets for coupling facility log streams for more information.