Public Network FAQs

What public network adapters does the SunPlex system support?

Currently, the SunPlex system supports Ethernet (10/100BASE-T and 1000BASE-SX Gb) public network adapters. Because new interfaces might be supported in the future, check with your Sun sales representative for the most current information.
What is the role of the MAC address in failover?

When a failover occurs, new Address Resolution Protocol (ARP) packets are generated and broadcast to the world. These ARP packets contain the new MAC address (of the new physical adapter to which the node failed over) and the old IP address. When another machine on the network receives one of these packets, it flushes the old MAC-IP mapping from its ARP cache and uses the new one.
Does the SunPlex system support setting local-mac-address?=true in the OpenBoot™ PROM (OBP) for a host adapter?

Yes. In fact, IP Network Multipathing requires that local-mac-address? must be set to true.
How much delay can I expect when IP Network Multipathing performs a switchover between adapters?

The delay could be several minutes. This is because when a IP Network Multipathing switchover is done, it involves sending out a gratuitous ARP. However, there is no guarantee that the router between the client and the cluster will use the gratuitous ARP. So, until the ARP cache entry for this IP address on the router times out, it is possible that it could use the stale MAC address.
How fast are failures of a network adapter detected?

The default failure detection time is 10 seconds. The algorithm tries to meet the failure detection time, but the actual time depends on the network load.

Cluster Member FAQs

Do all cluster members need to have the same root password?

You are not required to have the same root password on each cluster member. However, you can simplify administration of the cluster by using the same root password on all nodes.
Is the order in which nodes are booted significant?

In most cases, no. However, the boot order is important to prevent amnesia (refer to Quorum and Quorum Devices for details on amnesia). For example, if node two was the owner of the quorum device and node one is down, and then you bring node two down, you must bring up node two before bringing back node one. This prevents you from accidentally bringing up a node with out of date cluster configuration information.
Do I need to mirror local disks in a cluster node?

Yes. Though this mirroring is not a requirement, mirroring the cluster node's disks precludes against a non-mirrored disk failure taking down the node. The downside to mirroring a cluster node's local disks is more system administration overhead.
What are the cluster member backup issues?

You can use several backup methods for a cluster. One method is to have a node as the backup node with a tape drive/library attached. Then use the cluster file system to back up the data. Do not connect this node to the shared disks.

See the Sun Cluster 3.1 System Administration Guide for additional information on backup and restore procedures.
When is a node healthy enough to be used as a secondary node?

After a reboot, a node is healthy enough to be a secondary node when the node displays the login prompt.

Cluster Storage FAQs

What makes multihost storage highly available?

Multihost storage is highly available because it can survive the loss of a single disk, due to mirroring (or due to hardware-based RAID-5 controllers). Because a multihost storage device has more than one host connection, it can also withstand the loss of a single node to which it is connected. In addition, redundant paths from each node to the attached storage provide tolerance for the failure of a host bus adapter, cable, or disk controller.

Cluster Interconnect FAQs

What cluster interconnects does the SunPlex system support?

Currently, the SunPlex system supports Ethernet (100BASE-T Fast Ethernet and 1000BASE-SX Gb) and the SCI network interface cluster interconnects.

What is the difference between a "cable" and a transport "path?"

Cluster transport cables are configured using transport adapters and switches. Cables join adapters and switches on a component-to-component basis. The cluster topology manager uses available cables to build end-to-end transport paths between nodes. A cable does not map directly to a transport path.

Cables are statically "enabled" and "disabled" by an administrator. Cables have a "state," (enabled or disabled) but not a "status." If a cable is disabled, it is as if it were unconfigured. Cables that are disabled cannot be used as transport paths. They are not probed and therefore, it is not possible to know their status. The state of a cable can be viewed using scconf -p.

Transport paths are dynamically established by the cluster topology manager. The "status" of a transport path is determined by the topology manager. A path can have a status of "online" or "offline." The status of a transport path can be viewed using scstat(1M).
Consider the following example of a two-node cluster with four cables.
node1:adapter0 to switch1, port0 node1:adapter1 to switch2, port0 node2:adapter0 to switch1, port1 node2:adapter1 to switch2, port1
There are two possible transport paths that can be formed from these four cables.
node1:adapter0 to node2:adapter0 node2:adapter1 to node2:adapter1

Client Systems FAQs

Do I need to consider any special client needs or restrictions for use with a cluster?

Client systems connect to the cluster as they would any other server. In some instances, depending on the data service application, you might need to install client-side software or perform other configuration changes so that the client can connect to the data service application. See individual chapters in Sun Cluster 3.1 Data Services Installation and Configuration Guide for more information on client-side configuration requirements.

Administrative Console FAQs

Does the SunPlex system require an administrative console?

Yes.
Does the administrative console have to be dedicated to the cluster, or can it be used for other tasks?
The SunPlex system does not require a dedicated administrative console, but using one provides these benefits:
- Enables centralized cluster management by grouping console and management tools on the same machine
- Provides potentially quicker problem resolution by your hardware service provider
Does the administrative console need to be located "close" to the cluster itself, for example, in the same room?

Check with your hardware service provider. The provider might require that the console be located in close proximity to the cluster itself. No technical reason exists for the console to be located in the same room.
Can an administrative console serve more than one cluster, as long as any distance requirements are also first met?

Yes. You can control multiple clusters from a single administrative console. You can also share a single terminal concentrator between clusters.