Tuning Linux systems
This topic describes how to tune the Linux® operating system to optimize the performance of your WebSphere® Application Server.
About this task
Procedure
Firewalls typically have a connection expiration timeout. If there is no activity on a connection within the timeout interval, the connection is removed from the firewall routing tables. If connections between servers, such as a connection pool between a server and a backend database, are timed out by a firewall between the systems, attempts to reuse the connection fail until the connection is reestablished, causing errors and performance issues.
To avoid this type of problem, you can configure the TCP keepalive function to operate on an interval that is shorter than the firewall timeout. The TCP keepalive activity informs the firewall that the connection is still in use, so the connection does not expire and be flushed from the firewall tables.
To perform this tuning, first determine the firewall connection expiration timeout. The network administrator typically knows this information. Next, set the following three TCP tuning options to run TCP keepalive at an interval comfortably shorter than connection expiration timeout. Thus, for a firewall connection expiration timeout of 75 seconds, set the TCP tuning options to run TCP keepalive at an interval less than 75 seconds. Add the options to the /etc/sysctl.conf file to survive restarts.