Nodes

A node is a single processing unit within a system. For redundancy, nodes are deployed in pairs.

Each pair of nodes is known as an I/O group. Each node can be in only one I/O group.

Note: IBM® FlashSystem does not support systems with more than one I/O group. IBM SAN Volume Controller systems continue to support multiple I/O groups on long-term support releases only.

In enclosure-based systems, a node canister is equivalent to a node. The two node canisters in a control enclosure make an I/O group. Within a control enclosure, nodes communicate with each other via the enclosure hardware. For more details, see Expansion enclosures topic in the relevant hardware guide.

Nodes use Fibre Channel to communicate with hosts, external storage, other nodes (outside the enclosure) and Ethernet ports to communicate with hosts and external storage or other systems. Each node has a service IP address. The system also has one or two management IP addresses.

If Ethernet ports are used for I/O, nodes are configured with additional IP addresses.