You can migrate a Metro
Mirror relationship
to a Global Mirror relationship.
Scenario: I/O operations to the secondary VDisk can
be stopped during the migration
In this scenario, you have
the ability to stop I/O operations to the secondary VDisk during the
migration process.
To stop I/O operations to the secondary VDisk
while migrating a Metro
Mirror relationship
to a Global Mirror relationship,
you must specify the synchronized option when you create the Global Mirror relationship.
- Stop all host I/O operations to the primary VDisk.
- Verify that the Metro
Mirror relationship
is consistent.
Important: If the Metro
Mirror relationship
is not consistent when it is stopped, or if any host I/O operations
run between the Metro
Mirror relationship
being stopped and the Global Mirror relationship
being created, the updates are not copied to the secondary VDisk.
- Delete the Metro
Mirror relationship.
- Create the Global Mirror relationship
between the same two VDisks.
After the Global Mirror relationship
is created, you can start the relationship and resume host I/O operations.
Scenario: I/O operations to the secondary VDisk cannot
be stopped during the migration
In this scenario, you do
not have the ability to stop I/O operations to the secondary VDisk
during the migration process.
If I/O operations to the secondary
VDisk cannot be stopped, the data on the secondary VDisk becomes out-of-date.
When the Global Mirror relationship
is started, the secondary VDisk is inconsistent until all of the recent
updates are copied to the remote site.
If you do not require
a consistent copy of the VDisk at the secondary site, perform the
following steps to migrate from a Metro
Mirror relationship
to a Global Mirror relationship:
Important: The data on the secondary VDisk is not usable until
the synchronization process is complete. Depending on your link capabilities
and the amount of data that is being copied, this process can take
an extended period of time. You must set the background copy bandwidth
for the intercluster partnerships to a value that does not overload
the intercluster link.
- Delete the Metro
Mirror relationship.
- Create and start the Global Mirror relationship
between the same two VDisks.
If you require a consistent copy of the VDisk at the secondary
site, perform the following steps to migrate from a Metro
Mirror relationship
to a Global Mirror relationship:
- Delete the Metro
Mirror relationship.
- Create a Global Mirror relationship
between VDisks that were not used for the Metro
Mirror relationship.
This preserves the VDisk so that you can use it if you require a consistent
copy at a later time.
Alternatively, you can use the FlashCopy® feature to maintain a consistent
copy. Perform the following steps to use the FlashCopy feature to maintain a consistent
copy:
- Start a FlashCopy operation
for the Metro
Mirror VDisk.
- Wait for the FlashCopy operation
to complete.
- Create and start the Global Mirror relationship
between the same two VDisks. The FlashCopy VDisk
is now your consistent copy.