TuningMMapSessionManager (UNIX/Linux)

Thefollowing example describes the eect on process size when conguring the
persistence-type="mmap"usingthe manager-properties properties. For more information,
see“MMap Session Manager (UNIX Only)” in Sun Java System Web Server 7.0 Update 1
Developer’sGuide to JavaWeb Applications.
maxSessions = 1000
maxValuesPerSession = 10
maxValueSize = 4096
Thisexample would create a memory mapped le of size 1000 X 10 X 4096 bytes, or ~40 MB. As
thisis a memory mapped le, the process size will increase by 40 MB upon startup. The larger
thevalues you set for these parameters, the greater the increase in process size.
TuningCGI Stub Processes (UNIX/Linux)
InWeb Server, the CGI engine creates CGI stub processes as needed. On systems that serve a
largeload and rely heavily on CGI-generated content, it is possible for the CGI stub processes to
consumeall system resources. If this is happening on your server, the CGI stub processes can be
tunedto restrict how many new CGI stub processes can be spawned, their timeout value, and
theminimum number of CGI stub process that run at any given moment.
Note– If you have an init-cgi function in the magnus.conf le and you are running in
multi-processmode, you must add LateInit = yes to the init-cgi line.
Tunethe following settings to control CGI stubs. These settings are on the conguration's
PerformanceTab ⇒CGI sub tab.
■MinimumStubs Size: Controls the number of processes that are started by default. The rst
CGIstub process is not started until a CGI program has been accessed. The default value is
0.If you have an init-cgi directive in the magnus.conf le, the minimum number of CGI
stubprocesses are spawned at startup.
■MaximumStub Size: Controls the maximum number of CGI stub processes the server can
spawn.This is the maximum concurrent CGI stub processes in execution, not the
maximumnumber of pending requests. The default value is 16 and should be adequate for
mostsystems. Setting this too high might actually reduce throughput.
■CGIStub Timeout: Causes the server to kill any CGI stub processes that have been idle for
thenumber of seconds set by this directive. Once the number of processes is at the
minimumstubs size, it does not kill any more processes. The default is 30.
■CGITimeout: Limits the maximum time in seconds that CGI processes can run. The default
is–1, which means there is no timeout.
TuningCGIStub Processes (UNIX/Linux)
Chapter2 • Tuning Sun Java System Web Server 81