HP-UX NSA HTTP B.11.23.01.01 Release Notes

Limitations

Chapter 11

Limitations

NSA HTTP cache size management is not currently integrated with file system buffer cache

management. If the NSA HTTP product is installed, HP suggests that you verify and possibly

decrease the size of the file system buffer cache.

By default, the NSA HTTP maximum cache size percentage is 50 (50% of available system

memory). If the NSA HTTP maximum cache size percentage plus the minimum file system

buffer cache percentage (dbc_min_pct) is 100 percent or more, it is possible to have all of

system memory used for the NSA HTTP and file system caches. This will cause system

performance to degrade. The default value for dbc_min_pct is 5 (5%).

You can change the NSA HTTP maximum cache size percentage by editing

/etc/rc.config.d/nsahttpconf or using the nsahttp command. To change the file system

buffer cache values, set the dbc_min_pct and dbc_max_pct system parameters with the

kctune command. For more information, refer to the kctune (1M) man page.

Known Problems and Workarounds

If both the Web server and the Web client are running on the same system, the NSA HTTP

module, nsamod, may be busy even when no Web server is running. This condition may

happen if the Web client sends an HTTP GET request but does not immediately retrieve the

reply. In this case, nsamod will remain “busy” until the Web client reads the reply (for

example, by completing a recv() request).

This behavior has no side effects unless you try to deinstall the NSA HTTP product while

there is an un-read HTTP GET reply for a local Web client. Deinstalling the NSA HTTP

product when the nsamod module is busy will cause the system to reboot.

To avoid a system reboot, execute the following command after deregistering the NSA HTTP

ports (step 2 of the deinstallation process):

kcmodule nsamod=unused

If the above command successfully completes, you can use swremove to remove the NSA

HTTP product without causing swremove to reboot the system.