Explanation
This error might be caused by a problem on the primary system, a problem on the secondary system,
or a problem on the intersystem link. The problem might be a failure of a component, a component
becoming unavailable or having reduced performance because of a service action, or it might be that
the performance of a component dropped to a level where the Metro Mirror or Global Mirror
relationship cannot be maintained. Alternatively the error might be caused by a change in the
performance requirements of the applications that are using Metro Mirror or Global Mirror.
This error is reported on the primary system when the copy relationship has not progressed
sufficiently over a period. Therefore, if the relationship is restarted before all of the problems
are fixed, the error might be reported again when the time period next expires (the default period
is 5 minutes).
This error might also be reported because the primary system encountered read errors.
You might need to refer to the Copy Services features information in the software installation
and configuration documentation while you diagnose this error.
User Response
- If the 1920 error occurred previously on Metro Mirror or Global Mirror between the same systems
and all the following actions were attempted, contact your product support center to resolve the
problem.
- On both systems, check the partner Fibre Channel port mask to ensure that sufficient
connectivity is available. If the partner Fibre Channel port mask was changed recently, ensure that
the mask is correct.
- On the primary system that is reporting the error, correct any higher priority errors.
- On the secondary system, review the maintenance logs to determine whether the system was
operating with reduced capability at the time the error was reported. The reduced capability might
be because of a software upgrade, hardware maintenance to a node, maintenance to a backend disk
system or maintenance to the SAN.
- On the secondary system, correct any errors that are not fixed.
- On the intersystem link, review the logs of each link component for any incidents that would
cause reduced capability at the time of the error. Ensure that the problems are fixed.
- If a reason for the error was found and corrected, go to Action 11.
- On the primary system that is reporting the error, examine the statistics by using a SAN
productivity monitoring tool and confirm that all the Metro Mirror and Global Mirror requirements
that are described in the planning documentation are met. Ensure that any changes to the
applications that use Metro Mirror or Global Mirror are accounted for. Resolve any issues.
- On the secondary system, examine the statistics by using a SAN productivity monitoring tool and
confirm that all the Metro Mirror and Global Mirror requirements that are described in the software
installation and configuration documentation are met. Resolve any issues.
- On the intersystem link, examine the performance of each component by using an appropriate SAN
productivity monitoring tool to ensure that they are operating as expected. Resolve any issues.
- Mark the error as "fixed" and restart the Metro Mirror or
Global Mirror relationship.
When you restart the Metro Mirror or Global Mirror relationship, there is an initial period
during which Metro Mirror or Global Mirror performs a background copy to resynchronize the volume
data on the primary and secondary systems. During this period, the data on the Metro Mirror or
Global Mirror auxiliary volumes on the secondary system is inconsistent and the volumes cannot be
used as backup disks by your applications.
Note: To ensure that the system has the capacity to handle the background copy load, you might want
to delay restarting the Metro Mirror or Global Mirror relationship until there is a quiet period
when the secondary system and the SAN fabric (including the intersystem link) have the required
capacity. If the required capacity is not available, you might experience another 1920 error and the
Metro Mirror or Global Mirror relationship stops in an inconsistent state.
Note: If the Metro Mirror or Global Mirror relationship stopped in a consistent state
("consistent-stopped"), it is possible to use the data on the Metro Mirror or Global Mirror
auxiliary volumes on the secondary system as backup disks by your applications. Therefore, you might
want to start a FlashCopy of your Metro Mirror or Global Mirror auxiliary disks on the secondary
system before you restart the Metro Mirror or Global Mirror relationship. This means that you
maintain the current, consistent, image until the time when the Metro Mirror or Global Mirror
relationship is again synchronized and in a consistent state.
Possible Cause-FRUs or other:
Other:
- Primary system or SAN fabric problem (10%)
- Primary system or SAN fabric configuration (10%)
- Secondary system or SAN fabric problem (15%)
- Secondary system or SAN fabric configuration (25%)
- Intersystem link problem (15%)
- Intersystem link configuration (25%)