Sun Java System Application Server Enterprise Edition 8.1 2005Q2 High Availability Administration Guide

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### Configuring Double Networks

To enable HADB to tolerate single network failures, use IP multipathing if the operating system (for example, Solaris) supports it. Do not configure HADB with double networks on Windows Server 2003—the operating system does not work properly with double networks.

If your operating system is not configured for IP multipathing, and HADB hosts are equipped with two NICs, you can configure HADB to use double networks. For every host, the IP addresses of each of the network interface card (NIC) must be on separate IP subnets.

Within a database, all nodes must be connected to a single network, or all nodes must be connected to two networks.

Note –

Routers between the subnets must be configured to forward UDP multicast messages between subnets.

When creating an HADB database, use the –hosts option to specify two IP addresses or host names for each node: one for each NIC IP address. For each node, the first IP address is on net-0 and the second on net-1. The syntax is as follows, with host names for the same node separated by a plus sign (+):

    --hosts=node0net0name+node0net1name
    ,node1net0name+node1net1name
    ,node2net0name+node2net1name
    , ...

For example, the following argument creates two nodes, each with two network interfaces. The following host option is used to create these nodes:

    --hosts 10.10.116.61+10.10.124.61,10.10.116.62+10.10.124.62

Thus, the network addresses

- For node0 are `10.10.116.61` and `10.10.124.61`

- For node1 are `10.10.116.62` and `10.10.124.62`

Notice that `10.10.116.61` and `10.10.116.62` are on the same subnet, and `10.10.124.61` and `10.10.124.62` are on the same subnet.

In this example, the management agents must use the same subnet. Thus, the configuration variable `ma.server.mainternal.interfaces` must be set to, for example, `10.10.116.0/24`. This setting can be used on both agents in this example.

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