Cluster Interconnect

The cluster interconnects provide the hardware pathways for private-network communication between cluster nodes. Each interconnect consists of a cable that is connected in one of the following ways:

• Between two transport adapters

• Between a transport adapter and a transport switch

For more information about the purpose and function of the cluster interconnect, see Cluster Interconnect in Sun Cluster Concepts Guide for Solaris OS.

You do not need to configure a cluster interconnect for a single-host cluster. However, if you anticipate eventually adding more voting nodes to a single-host cluster configuration, you might want to configure the cluster interconnect for future use.

During Sun Cluster configuration, you specify configuration information for one or two cluster interconnects.

• If the number of available adapter ports is limited, you can use tagged VLANs to share the same adapter with both the private and public network. For more information, see the guidelines for tagged VLAN adapters in Transport Adapters.

• You can set up from one to six cluster interconnects in a cluster. While a single cluster interconnect reduces the number of adapter ports that are used for the private interconnect, it provides no redundancy and less availability. If a single interconnect fails, the cluster is at a higher risk of having to perform automatic recovery. Whenever possible, install two or more cluster interconnects to provide redundancy and scalability, and therefore higher availability, by avoiding a single point of failure.

You can configure additional cluster interconnects, up to six interconnects total, after the cluster is established by using the clsetup(1CL) utility.

For guidelines about cluster interconnect hardware, see Interconnect Requirements and Restrictions in Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS. For general information about the cluster interconnect, see Cluster-Interconnect Components in Sun Cluster Overview for Solaris OS and Sun Cluster Concepts Guide for Solaris OS.

Transport Adapters

For the transport adapters, such as ports on network interfaces, specify the transport adapter names and transport type. If your configuration is a two-host cluster, you also specify whether your interconnect is a point-to-point connection (adapter to adapter) or uses a transport switch.

Consider the following guidelines and restrictions:

• IPv6 – Sun Cluster software does not support IPv6 communications over the private interconnects.

• Local MAC address assignment – All private network adapters must use network interface cards (NICs) that support local MAC address assignment. Link-local IPv6 addresses, which are required on private-network adapters to support IPv6 public-network addresses, are derived from the local MAC addresses.

• Tagged VLAN adapters – Sun Cluster software supports tagged Virtual Local Area Networks (VLANs) to share an adapter between the private cluster interconnect and the public network. To configure a tagged VLAN adapter for the cluster interconnect, specify the adapter name and its VLAN ID (VID) in one of the following ways:

  • Specify the usual adapter name, which is the device name plus the instance number or physical point of attachment (PPA). For example, the name of instance 2 of a Cassini Gigabit Ethernet adapter would be ce2. If the scinstall utility asks whether the adapter is part of a shared virtual LAN, answer yes and specify the adapter's VID number.

  • Specify the adapter by its VLAN virtual device name. This name is composed of the adapter name plus the VLAN instance number. The VLAN instance number is derived from the formula (1000*V)+N, where V is the VID number and N is the PPA.

    As an example, for VID 73 on adapter ce2, the VLAN instance number would be calculated as (1000*73)+2. You would therefore specify the adapter name as ce73002 to indicate that it is part of a shared virtual LAN.

  For information about configuring VLAN in a cluster, see Configuring VLANs as Private Interconnect Networks in Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS. For general information about VLAN, see Administering Virtual Local Area Networks in System Administration Guide: IP Services.

• SPARC: Sun LDoms guest domains – Specify adapter names by their virtual names, vnetN, such as vnet0 and vnet1. Virtual adapter names are recorded in the /etc/path_to_inst file.

• SBus SCI adapters – The SBus Scalable Coherent Interface (SCI) is not supported as a cluster interconnect. However, the SCI-PCI interface is supported.

• Logical network interfaces – Logical network interfaces are reserved for use by Sun Cluster software.

See the scconf_trans_adap_*(1M) family of man pages for information about a specific transport adapter.

Transport Switches

If you use transport switches, such as a network switch, specify a transport switch name for each interconnect. You can use the default name switchN, where N is a number that is automatically assigned during configuration, or create another name.

Also specify the switch port name or accept the default name. The default port name is the same as the internal node ID number of the Solaris host that hosts the adapter end of the cable. However, you cannot use the default port name for certain adapter types, such as SCI-PCI.

Clusters with three or more voting nodes must use transport switches. Direct connection between voting cluster nodes is supported only for two-host clusters.

If your two-host cluster is direct connected, you can still specify a transport switch for the interconnect.

If you specify a transport switch, you can more easily add another voting node to the cluster in the future.