Tuning Solaris systems
The following tuning parameters are specific to the Solaris operating system. Because the Solaris operating system is not a WebSphere® Application Server product, be aware that it can change and results vary.
About this task
Procedure
Configure the following settings or variables according to your tuning needs:
- Solaris file descriptors (ulimit)
- Specifies the maximum number of open files supported. If the value of this parameter is too low, a Too many files open error is displayed in the WebSphere Application Server stderr.log file.
- Solaris TCP_TIME_WAIT_INTERVAL
- Notifies TCP/IP on how long to keep the connection control blocks closed. After the applications complete the TCP/IP connection, the control blocks are kept for the specified time. When high connection rates occur, a large backlog of the TCP/IP connections accumulates and can slow server performance. The server can stall during certain peak periods. If the server stalls, the netstat command shows that many of the sockets that are opened to the HTTP server are in the CLOSE_WAIT or FIN_WAIT_2 state. Visible delays can occur for up to four minutes, during which time the server does not send any responses, but CPU utilization stays high, with all of the activities in system processes.
- Solaris TCP_FIN_WAIT_2_FLUSH_INTERVAL
- Specifies the timer interval prohibiting a connection in the FIN_WAIT_2 state to remain in that state. When high connection rates occur, a large backlog of TCP/IP connections accumulates and can slow server performance. The server can stall during peak periods. If the server stalls, using the netstat command shows that many of the sockets opened to the HTTP server are in the CLOSE_WAIT or FIN_WAIT_2 state. Visible delays can occur for up to four minutes, during which time the server does not send any responses, but CPU utilization stays high, with all of the activity in system processes.
- Solaris TCP_KEEPALIVE_INTERVAL
- The keepAlive packet ensures that a connection stays in an active and established state
- Solaris kernel semsys:seminfo_semopm
- An entry in the /etc/system file can exist for this tuning parameter. This number is the maximum value of System V semaphore operations per semop call. The default value for this option is too low for highly concurrent systems.
- Connection backlog
- Change the following parameter when a high rate of incoming connection requests result in
connection failures:
ndd -get /dev/tcp tcp_conn_req_max_q ndd -set /dev/tcp tcp_conn_req_max_q 8000
- Large page support
- Using large pages can reduce the CPU overhead of managing a large JVM heap.