Physical planning requirements

 

Depending on how you plan to use independent disk pools, satisfy specific physical planning requirements.

 

Multisystem clustered environment (for switchable independent disk pools)

High-speed link (HSL) cables must be used to attach the expansion units to the systems in the cluster.

The expansion unit must be physically adjacent in the HSL loop to the alternate system or expansion unit owned by the alternative system. You can include a maximum of two systems (cluster nodes) on each HSL loop, though each system can be connected to multiple HSL loops. You can include a maximum of four expansion units on each HSL loop, though a maximum of three expansion units can be included on each loop segment. On an HSL loop containing two systems, two segments exist, separated by the two systems. All expansion units on one loop segment must be contained in the same device cluster resource group (CRG).

In order for an expansion unit to become switchable it must physically be the farthest away from the owning system on the loop segment.

An error will occur if you try to make an expansion unit switchable if there is another expansion unit farther away the owning system that has not become switchable.

The switchable expansion unit must be SPCN-cabled to the system unit that will initially serve as the primary node for the switchable hardware group (device CRG). The primary node might be a primary or secondary logical partition within the system unit. If using logical partitions, the system buses in the intended expansion unit must be owned and dedicated by the partition involved in the cluster.

 

Parent topic:

Planning for independent disk pools