DB2 10.5 for Linux, UNIX, and Windows

Configuring operating system TCP/IP keepalive parameters for high availability clients

About this task

For client systems that do not support the keepAliveTimeout parameter because of an operating system, platform or Java Development Kit (JDK) limitation, the TCP/IP keepalive settings can be set at the operating system level by adjusting certain parameters. These clients include Solaris 10.1 Fix Pack 2 and earlier.

For client systems that do support the keepAliveTimeout parameter adjusting operating system parameters can also allow for early detection of a non-responsive socket and for faster client reroute.

The values provided in these commands are suggested values, but you should fine-tune these settings based on your specific network and server capabilities.

Note: By altering these settings at an operating system level, this will affect all TCP/IP communications on the client.

Procedure

Configuring operating system TCP/IP parameters for clients that support the keepAliveTimeout parameter
If the client is waiting on a receive response from the server, the keepAliveTimeout parameter is enabled when the maximum number of retransmissions have finished. To specify the maximum number of retransmissions you can modify the following operating system parameters:
- On Linux: The tcp_retries2 parameter
- On Solaris and HP-UX: The tcp_ip_abort_interval parameter
- On Windows: The TcpMaxDataRetransmissions parameter
Configuring operating system TCP/IP parameters for clients that do not support the keepAliveTimeout parameter
Updating Solaris: For Solaris 10.1 Fix Pack 2 and earlier clients, change the following operating system keepalive parameter:
- tcp_keepalive_interval - sets a probe interval that is first sent out after a TCP connection is idle on a system-wide basis.
To display the value of the tcp_keepalive_interval parameter run the following command:
```
ndd -get /dev/tcp tcp_keepalive_interval 
```
To update the value of the tcp_keepalive_interval parameter run the following command:
```
ndd -set /dev/tcp tcp_keepalive_interval 
```

What to do next

For other client platforms, refer to your operating system documentation on how to set TCP/IP keepalive values.