Failure of the local storage system

If the local storage system fails, processing can be resumed within a short time using the target units of the remote storage system. There may be data inconsistency if asynchronous processing mode was set before local failure, or if local failure was preceded by failure of the remote link or target unit.
If paging is affected, the local system also fails (see section "Failure of the local storage system and of the local system").

In concurrent SRDF configurations it is first necessary to select the storage system or location where operation is to be resumed.

Actions on the local system

1. Use /ATTACH-DEVICE to attach the target units (see the “Commands” manual [1])

2. Set the target units to READY.
   If the remote storage system contains only target units affected by the failure, the entire remote storage system can be specified. Switchover takes place simultaneously for all the devices affected.

   /SET-REMOTE-COPY-ACCESS
     UNIT=*BY-SYMMETRIX(SERIAL-NUMBER=<remote serialnumber>
     ,LOGICAL-VOLUMES=*ALL-TARGETS),TARGET-ACCESS=*DIRECT
   

   For this function, the values DETACHED-DEVICES=*ACCEPT and NOT-DEFINED-DEVICES=*ACCEPT must be set for SYSTEM-ADMIN-SCOPE or TASK-ADMIN-SCOPE.

   If not all target units of the remote storage system are affected by the failure, the units must be specified separately. Device selection depends on the settings for SYSTEM-ADMIN-SCOPE or TASK-ADMIN-SCOPE and is made using:

   /SET-REMOTE-COPY-ACCESS 
     UNIT=*BY-VOLUME(VOLUME=<vsn>) / *BY-PUBSET(PUBSET=<cat-id>) /
          <MN of target unit>
     ,TARGET-ACCESS=*DIRECT 
   

   If the target unit was not synchronized with the source unit, transition to READY is rejected if PENDING-UPDATES are not allowed for the unit. This setting can be overridden by means of the following command:

   /SET-REMOTE-COPY-ACCESS
     UNIT=*BY-VOLUME(VOLUME=<vsn>) / *BY-PUBSET(PUBSET=<cat-id>) /
          <MN of target unit>
     ,TARGET-ACCESS=*DIRECT(ALLOW-PEND-UPDATES=*YES)
   

   The *BY-VOLUME operand may only be used if the target unit was READ-ONLY and is unique, or if the source unit was accessible, i.e. the VSN was readable on the unit. The *BY-PUBSET operand cannot be used for the switchover because of the failure.

3. Check data integrity (see section "Data integrity after a failure")

4. Import the pubsets and start the applications