Planning The Implementation; Disk Ownership - IBM N3700 A20 Setup

Planning the implementation

Regardless of whether or not you are installing a single-node or clustered
systems environment, planning and preparation are of particular importance.
Planning and preparation save time during the installation and configuration and
often prevent problems. Gather information and plan before the systems are
installed. Remember, we do not discuss the physical planning and mounting the
appliances and expansions into racks in this IBM Redpaper. You can obtain more
information about those subjects in IBM System Storage N series N3700
Hardware and Service Guide, GA32-0515.

Disk ownership

A System Storage N series cluster consists of two nodes that are able to
takeover/failover their resources or services to the associated counterpart nodes.
This functionality assumes that all resources can be accessed by each node.
That means both nodes must have access to all disks physically (cabling) and
logically (cluster software). The N3700 Model A20 combines both cluster nodes
in one shelf.
Each disk has a preferred ownership and "stays" on the owner node until a
takeover occurs. Ownership can be either to Node A or Node B (Figure 1).
Ownership Node
Ownership Node
Figure 1 Example disk ownership of Node A and Node B
2
IBM System Storage N3700 A20 Setup
A A A B B B A
Shelf 2
Shelf 1
B A B A B A B
A A B B B A B
A B A B A B A