Solaris
Tuning the following parameters has a significant performance impact for Solaris. They are set in the startupServer.sh script:
Solaris TCP_TIME_WAIT_INTERVAL
Solaris TCP_FIN_WAIT_2_FLUSH_INTERVAL
Solaris TCP_KEEPALIVE_INTERVAL When high connection rates occur, a large backlog of the TCP connections builds up and can slow server performance. The server can stall during certain peak periods. If this occurs, the netstat command will show that many of the sockets opened to port 80 were in the CLOSE_WAIT or FIN_WAIT_2 state.
Solaris file descriptors (ulimit)
Specifies the number of open files permitted.
If the value of this parameter is too low, the error message Too many files open is displayed in the WAS stderr.log.
Check the UNIX reference pages on ulimit for the syntax for different shells. For KornShell (ksh) the command is:
ulimit -n 1024Use the command ulimit -a to display the current values for all limitations on system resources.
The WAS startupServer.sh script sets this parameter to 1024 if its value is less than 1024.
Solaris kernel semsys:seminfo_semume
The semsys:seminfo_semume kernel tuning parameter limits the Max Semaphore undo entries per process and needs to be greater than the default (10 on Solaris 7). Because this setting specifies a maximum value, the parameter does not cause any additional memory to be used unless it is needed.
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 it via the /etc/system entry as follows:
set semsys:seminfo_semume = 1024
Solaris kernel semsys:seminfo_semopm
This setting is displayed SEMOPM if the /usr/sbin/sysdef command is run. There can be an entry in the /etc/system file for this tuning parameter. Set it via the /etc/system entry as follows:
semsys:seminfo_semopm = 200
Setting the virtual page size for WAS JVM
On Solaris, there may be a desire to increase the virtual page size for the WAS JVM. The command is entered as follows:
chatr +pi64M +pd64M /opt/WebSphere/AppServer/java/bin/PA_RISC2.0/native_threads/javawhere 64M stands for 64 MB, the recommended value.
Other Solaris TCP parameters
Customers have reported success with modifying other Solaris TCP parameters, including the following:
tcp_conn_req_max_q
tcp_comm_hash_size
tcp_xmit_hiwat Although significant performance differences have not been seen after raising these settings, the system might benefit.
Many other TCP parameters exist and can affect performance in a Solaris environment. For more information about tuning the TCP/IP Stack, see the article "Tuning your TCP/IP Stack and More" at:
http://www.sean.de/Solaris/soltune.html
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