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

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## Configuring Network Redundancy

Configuring a redundant network will enable HADB to remain available, even if there is a single network failure. You can configure a redundant network in two ways:

- On Solaris 9, you can set up network multipathing.

- Configure a double network, supported on all platforms except Windows Server 2003.

### Setting Up Network Multipathing

Before setting up network multipathing, refer to the Administering Network Multipathing section in the IP Network Multipathing Administration Guide.

#### To configure HADB host machines that already use IP multipathing:

1. Set network interface failure detection time.

   For HADB to properly support multipathing failover, the network interface failure detection time must not exceed one second (1000 milliseconds), as specified by the `FAILURE_DETECTION_TIME` parameter in `/etc/default/mpathd`. Edit the file and change the value of this parameter to 1000 if the original value is higher:

       FAILURE_DETECTION_TIME=1000

   To put the change into effect, use this command:

       pkill -HUP in.mpathd

2. Set up IP addresses to use with HADB.

   As described in the IP Network Multipathing Administration Guide, multipathing involves grouping physical network interfaces into multipath interface groups. Each physical interface in such a group has two IP addresses associated with it:

   - a physical interface address used for transmitting data.

   - a test address for Solaris internal use only.

   Specify only one physical interface address from the multipath group when you use `hadbm create --hosts`.

##### Example 2–1 Setting up Multipathing

Suppose there are two host machines named host1 and host2. If they each have two physical network interfaces, then set up the two interfaces as a multipath group. Run `ifconfig -a` on each host.

The output on host1 is:

    bge0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4>
    mtu 1500 index 5 inet 129.159.115.10 netmask ffffff00 broadcast 129.159.115.255
    groupname mp0

    bge0:1: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER>
    mtu 1500 index 5 inet 129.159.115.11 netmask ffffff00 broadcast 129.159.115.255

    bge1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4>
    mtu 1500 index 6 inet 129.159.115.12 netmask ffffff00 broadcast 129.159.115.255
    groupname mp0

    bge1:1: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER>
    mtu 1500 index 6 inet 129.159.115.13 netmask ff000000 broadcast 129.159.115.255

The output on host2 is:

    bge0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4>
    mtu 1500 index 3 inet 129.159.115.20 netmask ffffff00 broadcast 129.159.115.255
    groupname mp0

    bge0:1: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER>
    mtu 1500 index 3 inet 129.159.115.21 netmask ff000000 broadcast 129.159.115.255

    bge1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4>
    mtu 1500 index 4 inet 129.159.115.22 netmask ffffff00 broadcast 129.159.115.255
    groupname mp0

    bge1:1: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER>
    mtu 1500 index 4 inet 129.159.115.23 netmask ff000000 broadcast 129.159.115.255

In this example, the physical network interfaces on both hosts are listed after `bge0` and `bge1`. Those listed after `bge0:1` and `bge1:1` are multipath test interfaces (marked DEPRECATED in the `ifconfig` output), as described in the IP Network Multipathing Administration Guide.

To set up HADB in this environment, select one physical interface address from each host. In this example, HADB uses IP address 129.159.115.10 from host1 and 129.159.115.20 from host2. To create a database with one database node per host, use the command `hadbm create --host`. For example

    hadbm create --host 129.159.115.10,129.159.115.20

To create a database with two database nodes on each host, use the command:

    hadbm create --host 129.159.115.10,129.159.115.20,
    129.159.115.10,129.159.115.20

In both cases, you must configure the agents on host1 and host2 with separate parameters to specify which interface on the machines the agents should use. So, on host1 use:

    ma.server.mainternal.interfaces=129.159.115.10

And on host2 use:

    ma.server.mainternal.interfaces=129.159.115.20

For information on the `ma.server.mainternal.interfaces` variable, see Configuration File.

### 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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