Installation guide

Tune the Shared Memory Segments
152 Web Agent Installation Guide
Tune the Shared Memory Segments
If you install an Apache or Sun Java System Web Agent on Solaris or HP-UX
systems, you must tune the operating system‘s shared memory settings for the
Web Agent to function correctly. By increasing the operating system‘s shared
memory segments, you improve the performance of the Web Agent. The
variables that control shared memory segments are defined in the operating
system‘s specification file.
For AIX operating systems, you must run the following command before starting
an Apache server:
export EXTSHM=ON
Note: You may need to tune the shared memory segments if you are using
Linux. For more information about the shared memory segments and how to
tune them, see the documentation for your particular operating system.
To increase shared memory segments
1. Follow the appropriate procedure for your operating system:
■ Solaris: Open the /etc/system file, using the editor of your choice.
■ HP-UX: Start the System Administration Manager (SAM) utility
2. Modify the shared memory variables using one of the following methods:
■ Solaris: Add the variables shown in the following list and configure them
using the recommended settings shown in the examples. Use the
following syntax:
set shmsys:shminfo_shmmax=33554432
■ HP-UX: Using the SAM utility, select Kernel Configuration, Configurable
Parameters. SAM displays a set of variables. Highlight and modify each
one in the following list using the recommended settings shown in the
examples.
shmsys:shminfo_shmmax
Specifies the maximum shared memory segment size. Controls the
maximum size of the Agent resource and session cache.
Note: To estimate the amount of memory segments required, allocate
4KB/entry in each cache, or view cache usage statistics in the OneView
Monitor. See the Web Agent Configuration Guide for more information
about using the OneView Monitor.
Example: 33554432 (32 mb) for busy sites that need large cache
capacity.
shmsys:shminfo_shmmin
(Not required for Solaris) Minimum shared memory segment size.
Controls the minimum size of the Agent resource and session cache.