The system layer affects how the system interacts
with a SAN Volume Controller system and other external Lenovo Storage V series systems.
An IBMLenovo Storage V series system is in either the replication layer or
the storage layer.
Differences between the storage layer and the replication
layer
This table compares the characteristics and requirements
of storage layer and replication layer systems.
Table 1. Comparison of storage layer and replication layer systems
| Storage layer |
Replication layer |
- 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 a SAN Volume Controller system.
- The system cannot use another Lenovo Storage V series system that is configured with storage-layer as external
storage.
|
- The system can complete Metro Mirror and Global Mirror replication with other replication-layer systems
or a SAN Volume Controller system.
- The system cannot provide external storage for a replication-layer
system or a SAN Volume Controller system.
- The system can use another Lenovo Storage V series system that is configured with storage-layer as external
storage.
|
A Lenovo Storage V series 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 to complete Global Mirror or Metro Mirror replication with a SAN Volume Controller system.
Changing the layer of a Lenovo Storage V series system
To change the storage layer of an existing Storwize system with internal
storage before you add a second system into the SAN zone,
you do not need to stop I/O operations.
However, if the system has Fibre Channel (FC) connections
to another Lenovo Storage V series or SAN Volume Controller system in the SAN fabric, I/O operations must be stopped
temporarily. In this scenario, the FC ports must be disabled (for
example, by unplugging all the FC ports, changing zoning, disabling
switch ports) before you change the system layer. Then, you must
re-enable the FC ports.
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 Lenovo Storage V series system.
- No system partnerships can be defined.
- No Lenovo Storage V series system can be visible on the SAN fabric.
To change the layer of a system, follow these general
steps:
- Use the svc_lssystem.html#chsystem 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 svc_requestdiscovery_21ifux.html#lsvc_requestdiscovery_21ifux command to ensure that the system detects
any fabric changes that were done in step 3.
- Enter the one of the following commands to switch the system to
the appropriate layer.
- To switch to the replication layer, enter the chsystem command.
- To switch to the storage layer, enter the chsystem command.
- If the SAN configuration was changed in step 2, restore the normal SAN configuration.
- Run the svc_requestdiscovery_21ifux.html#lsvc_requestdiscovery_21ifux command to update the list of MDisks.