Node configuration details
Apply these configuration details to SAN Volume Controller nodes to ensure that you have a valid configuration.
Host bus adapters and nodes
SAN Volume Controller 2145-CG8 and SAN Volume Controller 2145-CF8 nodes contain one 4-port HBA.
SAN Volume Controller 2145-CG8 optionally contains a two-port Fibre Channel over Ethernet (FCoE) converged network adapter (CNA) in addition to the four-port HBA.
SAN Volume Controller 2145-DH8 and SAN Volume Controller 2145-SV1 nodes contain a mix of different supported network adapters and compression accelerators. For specific information on what the system supports, see the optional features topic.
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: SAN Volume Controller 2145-SV1.
Volumes
Each node presents a volume to the SAN through Fibre Channel ports, FCoE ports, iSCSI ports, or SAS ports. Each volume is accessible from the two nodes in an I/O group. Each HBA port can recognize up to eight paths to each logical unit (LU) that is presented by the clustered system. The hosts must run a multi-pathing device driver before the multiple paths can resolve to a single device. You can use fabric zoning to reduce the number of paths to a volume that are visible by the host.
Increased connectivity across SAN fabrics
SAN Volume Controller 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
- 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 feature 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 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.
Fibre Channel connection
SAN Volume Controller supports shortwave and longwave Fibre Channel connections between SAN Volume Controller nodes and the switches that they are connected to.
To avoid communication between nodes that route across interswitch links (ISLs), connect all SAN Volume Controller nodes to the same Fibre Channel or FCF switches.
No ISL hops are permitted among the SAN Volume Controller 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 SAN Volume Controller nodes that are in the same system though different I/O groups. If your configuration requires more than three ISL hops for SAN Volume Controller nodes that are in the same system but in different I/O groups, contact your IBM® service representative.
To avoid communication between nodes and storage systems that are being routed across ISLs, connect all storage systems to the same Fibre Channel switches as the SAN Volume Controller nodes. One ISL hop between the SAN Volume Controller nodes and the storage controllers is permitted. If your configuration requires more than one ISL, contact your IBM service representative.
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 SAN Volume Controller nodes. One ISL hop between the SAN Volume Controller nodes and the storage systems is permitted. If your configuration requires more than one ISL, contact your IBM service representative.
In larger configurations, it is common to have ISLs between host systems and the SAN Volume Controller nodes.
Port speed
| Model | Adapters supported |
|---|---|
| 2145-CF8 | 8 Gbps FC |
| 2145-CG8 | 8 Gbps FC, 10 Gbps Ethernet |
| 2145-DH8 | 8 Gbps FC, 16 Gbps FC, 10 Gbps Ethernet |
| 2145-SV1 | 16 Gbps FC, 10 Gbps Ethernet |
- The 8 Gbps FC adapter supports connection speeds of 2 Gbps, 4 Gbps and 8 Gbps.
- 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:
- The 10 Gbps Ethernet adapter supports a connection speed of 10 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.