An IBM® Storwize® family system
is in one of two layers: the replication layer or the storage
layer.
The system layer affects how the system interacts with IBM Spectrum Virtualize™
and external Storwize family systems.
Differences between the storage layer and the replication
layer
In storage layer, a
Storwize family
system has the following characteristics and requirements:
- The system can
complete Metro
Mirror and Global Mirror replication with other
storage-layer systems.
- The system can provide
external storage for replication-layer systems or SAN Volume Controller.
- The system cannot use another Storwize family system that is configured with
storage-layer as external storage.
In replication layer, a
Storwize family
system has the following characteristics and requirements:
- The system can
complete Metro
Mirror and Global Mirror replication with other
replication-layer systems or SAN Volume Controller.
- The system cannot
provide external storage for a replication-layer system or SAN Volume Controller.
- The system can use another Storwize family system that is configured with storage-layer as external storage.
A Storwize family system is in the storage layer
by default, but the layer can be changed. For example, you might want to change a Storwize V7000 system to a replication layer if
you want to use it to complete Global Mirror or Metro
Mirror with a SAN Volume Controller system.
Changing the layer of a Storwize family system
Before you change the system layer, the following conditions must be met:
- No host object can be configured with worldwide port names (WWPNs) from a Storwize family system.
- No system partnerships can be defined.
- No Storwize family system can be
visible on the SAN fabric.
The layer can be changed during normal host I/O.
To change the layer of a system, follow these general steps:
- Use the lssystem command to
check the current system layer.
- Configure SAN zoning so that the
system whose layer you are changing is not visible to any other system.
- Ensure that all other configuration requirements are met.
- Run the detectmdisk command to ensure that the system detects any fabric changes
that were done in step 3.
- Enter chsystem -layer
replication to switch to the replication layer or chsystem -layer storage to switch to the
storage layer.
- If the SAN configuration was changed in step 2,
restore the normal SAN configuration.
- Run the detectmdisk command to update the list of MDisks.