Configuring high-speed external caching through the web server

IBM® HTTP Server for Windows 2003 operating systems contains a high-speed cache referred to as the Fast Response Cache Accelerator, or cache accelerator. The Fast Response Cache Accelerator is available on Windows 2003 operating systems and AIX® platforms. However, support to cache dynamic content is only available on Windows 2003 operating systems. You can enable cache accelerator to cache static and dynamic content.

Before you begin

Restriction on using the fast response cache accelerator (FRCA) : The FRCA, which is based on the IBM Advanced Fast Path Architecture (AFPA), is not supported on the Microsoft Windows Vista , Windows 2008, or any later Windows operating systems. IBM HTTP Server will fail to start if the FRCA is enabled in the configuration file. This is a permanent restriction.

1. Configure WebSphere Application Server to enable Fast Response Cache Accelerator.
   It is important to follow all of the steps for every application server in the cluster.
   1. Turn on servlet caching for each application server that uses the cache accelerator.
   2. Configure an external cache group on the application server:
      1. Click Servers > Server Types > WebSphere application servers > server_name > Container services > Dynamic cache service > External cache groups.
      2. Click New on the External cache group administrative console page to define an external cache group named afpa for each application server that uses the cache accelerator.
      3. In the External cache group field, type afpa and apply the changes.
   3. Add a member to the group with an adapter bean name of com.ibm.ws.cache.servlet.Afpa.
      1. Click Afpa > External cache group members.
      2. Click New on the External cache group members administrative console page.
      3. In the AdapterBean name field, type com.ibm.ws.cache.servlet.Afpa.
      4. In the Address field, enter an unused port number.
   4. Add a cache policy in the cachespec.xml file for the servlet or JSP file you want to cache. Add the following property to the cache policy:

      <property name="ExternalCache">afpa</property>
      

2. Enable cache accelerator on IBM HTTP Server for distributed platforms:
   1. Add the following directives to the end of the httpd.conf file:
      • AfpaEnable
      • AfpaCache on
      • AfpaLogFile "app_server_root\IBMHttpServer\logs\afpalog" V-ECLF
      • Deprecated feature: IBM HTTP Server 1.3.x - LoadModule afpaplugin_module app_server_root\bin\afpaplugin.dll
      • IBM HTTP Server 2.0 - LoadModule afpaplugin_20_module app_server_root\bin\afpaplugin_20.dll
      • AfpaPluginHost WAS_Hostname:port, where WAS_Hostname is the host name of the application server and port is the port you specified in the Address field while configuring the external cache group member
   The LoadModule directive loads the IBM HTTP Server plug-in that connects the Fast Response Cache Accelerator to the WebSphere Application Server fragment cache.
   If multiple IBM HTTP Servers are routing requests to a single application server, add the directives to the httpd.conf file for each of these IBM HTTP Servers on distributed platforms.
   If one IBM HTTP Server is routing requests to a cluster of application servers, add the AfpaPluginHost WAS_Hostname:port directive to the httpd.conf file for each application server in the cluster. For example, if there are three application servers in the cluster, add the following directives to the httpd.conf file:

   • LoadModule afpaplugin_module app_server_root/bin/afpaplugin.dll
   • AfpaPluginHost WAS1_Hostname:port1
   • AfpaPluginHost WAS2_Hostname:port2
   • AfpaPluginHost WAS3_Hostname:port3