Figure 2-7, a URz pair created with the delta resync option is defined as a pair but no copy operation is performed (Hold status). Actual copy operation will not be performed until when the failure occurs and delta resync operation is performed. Note that there are several requirements to create a URz pair for delta resync operation, such as you need to specify the unused mirror ID. For detailed information about the requirements of creating a URz pair for delta resync operation, see section Requirements for Creating URz Pair for Delta Resync Operation.
For the information about the delta resync operation that will be performed when a failure occurs in the configuration shown in
Figure 2-7, see the next section. Note that the URz pair need to be in Hold status if you want to form the delta resync operation when the failure occurs. However, the URz pair status may be changed to Hlde for example when the cache memory or shared memory error occurs in TCz Synchronous secondary site, or when no journal cannot be obtained in TCz Synchronous secondary site because of the failure in the master journal volume or occurrence of the pinned track. If the status of the URz pair for delta resync operation changes to Hlde, follow the steps in section Restoring a Pair of Data Volumes and change the pair status to Hold again.
Switching the Master Journal Group of URz
When a failure occurs on the primary site in
Figure 2-7 (3DC multi-target configuration), the URz pair for delta resync operation can use the journal group in TCz Synchronous secondary site as the master journal group. To switch the master journal group, first change TCz Synchronous secondary site to the primary site by using Business Continuity Manager, then perform the delta resync operation on the primary data volume of the URz pair in Hold status. The following figure shows an example.
Chapter 3 Preparing for Universal Replicator z/OS Operations |
