Partnerships

Partnerships are used to connect systems together to enable migration, data replication, and high-availability solutions.

A system can have partnerships with up to three remote systems. The connectivity for each partnership can be either Fibre Channel or IP. Systems also become indirectly associated with each other through partnerships. If two systems each have a partnership with a third system, those two systems are indirectly associated. A maximum of four systems can be directly or indirectly associated with each other.

A partnership configuration requires actions on both systems involved. This ensures that there is authority to access each system and share data between them.

You can create a partnership in the following ways:

By using Fibre Channel connectivity.
By using Partnerships using IP Connectivity.

Policy-based Replication

To use partnerships for policy-based replication (asynchronous or high-availability), IP connectivity is required between management IP addresses of partnered systems.

Replication management requires access to the REST API on the remote system. Replication setup using the management GUI requires access to the management GUI of the remote system. Ensure that firewalls between the systems allow inbound traffic to port 7443 and 443 on the system management IP address.

Note: The communication on port 7443 and port 443 between the two partnered systems must occur on the default management IP address of each system.

The management traffic uses authentication certificates to prevent unauthorized access and ensure secure communications between the systems. Therefore, ensure that valid authentication certificates are installed on both the systems. For more information, see Configuring system certificates.

Background copy management

Certain types of replication differentiate between foreground host writes and background synchronisation traffic. The background copy rate is specified as a percentage of the partnership link bandwidth that is available to background synchronisation activities. Policy-based replication treats all traffic as background work so the background copy rate should be set to 100% if the system is using only policy-based replication.

HyperSwap, Metro Mirror, and Global Mirror (if supported by your system) use the background copy rate to control synchronisation traffic. Multi-cycling Global Mirror (Global Mirror with Change Volumes) uses only background copy therefore to achieve the best possible recovery point the background copy rate should be set to 100%. If you are using Metro Mirror, HyperSwap or non-cycling Global Mirror on your system, a lower value should be used to ensure that there is sufficient bandwidth to replicate host writes.

Replication between IBM Storage Virtualize systems

Systems that run IBM® Storage Virtualize software are in one of two layers: the replication layer or the storage layer.

A SAN Volume Controller system is always in the replication layer.
A FlashSystem is in the replication layer by default, but the system can be configured to be in the storage layer instead.

Partnership states

The state of the partnership helps determine whether the partnership operates as expected. A partnership can have the following states:

Configured: Both the local and remote systems have a partnership that is defined and are running as expected.
Partial Local: For the partnership to be fully configured, you must create a partnership from the remote system to the local system.
Local Stopped: Indicates that the partnership is defined on both the systems, but the partnership is stopped on the local system.
Remote Stopped: Indicates that the partnership is the defined on both the systems, but the partnership is stopped on remote system.
Partial Local Stopped: Indicates that only the local system has the partnership that is defined and the partnership is stopped on the local system.
Local Excluded: Indicates that both the local system and the remote system have the partnership that is defined, but the local system is excluding the link to the remote system. This state usually occurs when the link between the two systems is compromised by too many errors or slow response times of the partnership.
Remote Excluded: Indicates that both the local system and the remote system are defined in a partnership, but the remote system is excluding the link to the local system. This state usually occurs when the link between the two systems is compromised by too many errors or slow response times of the partnership.
Exceeded: Indicates that the partnership is unavailable because the network of systems exceeds the number of systems that are allowed in partnerships. To resolve this error, reduce the number of systems that are in partnerships in this network.
Not Present: Indicates that the remote system is not visible. This state can be caused by a problem with the connectivity between the local and remote system or if the remote system is unavailable.