Increasing TCP/IP Performance on Solaris 2.6 Systems

If you are running your Solaris 2.6 system with a large TCP window, and you experience slowdowns during periods of high network traffic, you should decrease the TCP default maximum retransmission timeout interval variable (tcp_rexmit_interval_max) to 60000.

1. As superuser type:

   ---

   # ndd -set /dev/tcp tcp_rexmit_interval_max 60000
   

   ---

The changes are immediate, and they affect all the TCP connections in the system. However, the changes will be lost when you reboot your machine.

You may not need to perform this workaround if you use a smaller TCP window (for example, an 8 Kbyte or a 16 Kbyte window).

To avoid losing the TCP/IP setting, you can put the parameter change in a run control script in the /etc/rc2.d directory, similar to the following example.

#!/sbin/sh
# Local kernel modifications
#
case "$1" in
'start')
	echo "Setting local kernel parameters...\c"
	ndd -set /dev/tcp tcp_rexmit_interval_max 60000
	echo ""
	;;
'stop')
	echo "No kernel parameters changed."
	;;
*)
	echo "Usage: $0 {start|stop}"
	;;
esac
exit 0