Tuning Solaris
Solaris file descriptors (ulimit)
Description: Specifies the number of open files permitted. If the value of this parameter is too low, a Too many files open error displays in the WebSphere Application Server stderr.log.
How to view or set: Check the UNIX reference pages on ulimit for the syntax of different shells. For KornShell (ksh) use the ulimit -n 1024 command. Use the ulimit -a command to display the current values for all limitations on system resources.
Default value: None
Recommended value: 2000
Solaris TCP_TIME_WAIT_INTERVAL
Description: Notifies the TCP/IP how long to keep closed connection control blocks. 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 accumulate 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 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.
How to view or set: Use the get command to determine the current interval and the set command to specify an interval of 60 seconds. For example:
ndd -get /dev/tcp tcp_time_wait_interval
ndd -set /dev/tcp tcp_time_wait_interval 60000
Default value: The Solaris default time wait interval is 2400000 milliseconds.
Recommended value: 60000 milliseconds.
Solaris TCP_FIN_WAIT_2_FLUSH_INTERVAL
Description: Specifies the timer interval prohibiting a connection in FIN_WAIT_2 to remain in that state. When high connection rates occur, a large backlog of TCP/IP connections accumulate 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 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.
How to view and set: You can set the current interval to 67.5 seconds by using the following commands:
ndd -get /dev/tcp tcp_fin_wait_2_flush_interval
ndd -set /dev/tcp tcp_fin_wait_2_flush_interval 67500
Default value: The Solaris default is 675000.
Recommended value: 67500
Solaris TCP_KEEPALIVE_INTERVAL
Description: The keepAlive packet ensures that a connection stays in an active/ESTABLISHED state.
How to view or set: Use the ndd command to determine the current value or to set the value. For example:
ndd -set /dev/tcp tcp_keepalive_interval 300000
Default value: 7200000 milliseconds.
Recommended value: 300000 milliseconds.
Solaris kernel semsys:seminfo_semume
Description: Limits the Max Semaphore undo entries per process. Because this setting specifies a maximum value, the parameter does not cause use of additional memory unless it is needed.
How to view or set: This value is displayed as SEMUME if the /usr/sbin/sysdef command is run. There can be an entry in the /etc/system file for this tuning parameter. Set this parameter through the /etc/system entry as follows:
set semsys:seminfo_semume = 1024
Default value: 10
Recommended value: None
Solaris kernel semsys:seminfo_semopm
Description: Displays as SEMOPM if the /usr/sbin/sysdef command is run. An entry in the /etc/system file can exist for this tuning parameter.
How to view or set: Set this parameter through the /etc/system entry as follows:
semsys:seminfo_semopm = 200
Default value: None
Recommended value: 16384
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