Planning for a direct-attached configuration

A direct-attached configuration dedicates entire port bandwidth to be used for a specific connection. Planning must account for the volume of expected traffic before you decide how many ports are used in a direct-attached configuration.

The system offers multiple options in deciding how to create a direct-attached configuration. Bandwidth requirements for a direct-attached configuration make it important to determine the volume of expected traffic in deciding the number of ports. For example, if a system to system direct-attached link is configured between nodes, then the link might carry inter-node traffic such as FlashCopy data. Hence, enough system to system bandwidth needs to be available so that it can carry all possible intra-node traffic without any bandwidth bottleneck.

The following guidelines are provided for direct-attached configurations.
Note: One or more Fibre Channel host adapters must be installed for the system to support these direct attachment configurations.
  1. Fibre Channel direct attachment to host systems.

    The system allows direct attachment connectivity between its Fibre Channel ports and host ports. Host systems can be connected to 32 Gb Fibre Channel ports or 16 Gb Fibre Channel ports on the system. No special configuration is needed for host systems that are using this configuration.

  2. Fibre Channel direct attachment between nodes in a system.

    Direct connection of the system Fibre Channel ports without using a Fibre Channel switch is supported. Such direct connections between the system nodes might be useful in small configurations where no Fibre Channel switch exists. Ensure that sufficient bandwidth is provisioned between nodes to accommodate all the intra-node traffic.

    For example, to connect twin control enclosures by using two ports of a Fibre Channel adapter in each node canister, complete the minimal cabling shown in Figure 1.
    Figure 1. Cabling with minimal connectivity
    Back view of Fibre Channel ports in twin FlashSystem 9100 control enclosures, with direct cabling by using four cables
    To increase performance, use all four ports to connect node canisters with eight cables, as shown in Figure 2.
    Figure 2. Cabling for a high-performance system
    Back view of Fibre Channel ports in twin FlashSystem 9100 control enclosures, with direct cabling by using eight cables

Storwize® V7000 Gen2 supports 16 Gb Fibre Channel ports. Node to host and node to node direct attachment is supported on all 32 Gb Fibre Channel ports and 16 Gb Fibre Channel ports.