Node configuration details

Apply these configuration details to nodes to ensure that you have a valid configuration.

Host bus adapters and nodes

SAN Volume Controller 2145-DH8 , SAN Volume Controller 2145-SV1 , SAN Volume Controller 2145-SV2, or SAN Volume Controller 2145-SA2 nodes contain a mix of different supported network adapters and compression accelerators. For specific information on what the system supports, see Optional features.

On SAN Volume Controller 2145-SV1 nodes, you can change which physical FC or FCoE port is assigned to each FC I/O port ID and worldwide port name (WWPN). For more information, see Fibre Channel port numbers: 2145-SV1.

For information about supported hardware, see the following website: www.ibm.com/support.

Volumes

Each node can present a volume (SCSI logical unit) to a host through network ports of the node. Each volume is accessible from the two nodes in an I/O group. Each host network port can recognize up to eight paths to each logical unit (LU) that is presented by the system. The hosts must run a multipathing device driver before the multiple paths can resolve to a single device. You can use fabric zoning, VLANs, or port masking to reduce the number of paths to a volume that are visible by the host. The network port types are Ethernet (iSCSI), Fibre Channel, and Fibre Channel over Ethernet.

Increased connectivity across SAN fabrics

The system supports more than four Fibre Channel and FCoE ports per node with the following restrictions:

  • Systems with a combined total of more than four Fibre Channel and FCoE ports on a node must be running version 6.4.0 or later.
  • Systems with more than four total FC and FCoE ports cannot establish a remote copy partnership to another system at a version earlier than 6.4.0.
  • Systems at 6.4.0 or later in partnership to systems at an earlier version cannot add a node that results in more than four combined FC and FCoE ports. Activating more ports by enabling FCoE or installing new hardware on existing nodes in the system is also not allowed.

To resolve these limitations, you must update the software on the remote system to 6.4.0 or later or disable the additional hardware by using the chnodehw -legacy CLI command.

Optical connections

Valid optical connections are based on the fabric rules that the manufacturers impose for the following connection methods:
  • Host to a switch
  • Back end to a switch.
  • Inter-switch links (ISLs)

Optical fiber connections can be used between a node and its switches.

Systems that use the intersystem Metro Mirror and Global Mirror functions can use optical fiber connections between the switches, or they can use distance-extender technology that is supported by the switch manufacturer.

Ethernet connection

To ensure system management failover operations, Ethernet port 1 on all nodes must be connected to the same set of subnets. If used, Ethernet port 2 on all nodes must also be connected to the same set of subnets. However, the subnets for Ethernet port 1 do not have to be the same as Ethernet port 2.

For host multipathing failover, node iSCSI ports must match between the two nodes in an I/O group.

Fibre Channel connection

The system supports shortwave and longwave Fibre Channel connections between nodes and the switches to which they are connected.

No ISL hops are permitted among the nodes within the same I/O group, except in a stretched system configuration with ISLs. (For more information, see the topic about using interswitch links to create a stretched system configuration.) However, no more than three ISL hops are permitted among nodes that are in the same system though different I/O groups. If your configuration requires more than three ISL hops for nodes that are in the same system but in different I/O groups, contact your support center.

Avoid communication between nodes and storage systems that are being routed across ISLs. To do so, connect all storage systems to the same Fibre Channel or FCF switches as the nodes. One ISL hop between the nodes and the storage systems is permitted. If your configuration requires more than one ISL, contact your support center.

In larger configurations, it is common to have ISLs between host systems and the nodes.

Port speed

The system supports the following types of adapters:
Table 1. Adapters
Model Adapters supported
2145-DH8 8 Gbps FC, 16 Gbps FC, 10 Gbps Ethernet
2145-SV1 16 Gbps FC, 10 Gbps Ethernet, 25 Gbps Ethernet
  • The 16 Gbps FC adapter supports a connection speed of 16 Gbps. It also supports certain 8 Gbps switches. For more information, see the following site:

    www.ibm.com/support

  • The 10 Gbps Ethernet adapter supports a connection speed of 10 Gbps.
  • The 25 Gbps Ethernet adapter supports a connection speed of 25 Gbps.

Fibre Channel ports on SAN Volume Controller 2145-DH8 nodes can operate at 16 Gbps if you use 16 Gbps Fibre Channel adapters. The ports can operate at 8 Gbps if you use 8 Gbps Fibre Channel adapters. The 16 Gbps Fibre Channel ports are supported only when connected to a 16 Gbps Fibre Channel switch. The ports are not supported on 8 Gbps, 4 Gbps, or 2 Gbps speed switches.