IBM Content Navigator, Version 2.0.3 Supports: FileNet Collaboration Services

Configuring cache assistance for large file downloads

When many users concurrently download a large file from the content repository, users can experience download performance problems and possible service outages. To prevent performance problems, IBM® FileNet® Collaboration Services can be configured to redirect the content requests to bypass the application server.

Before you begin

Ensure that the IBM HTTP Server plug-in for WebSphere® Application Server is installed on the server that hosts IBM FileNet Collaboration Services.

About this task

Redirected content requests during peak demand times benefit organizations with a wide-scale network for its content management system. For example, most employees of a large enterprise might use IBM Connections to share files on the content repository. In this example, the corporate network has a WebSphere Application Server deployment, which is configured to process a maximum of 100 threads at one time. Even with server clustering, the application server deployment can process a maximum of 500 concurrent requests. The chief executive officer office posts a 200 MB video to announce quarterly revenue. Thousands of employees receive notifications about the video and try to download it on the company network immediately. A single download of the file lasts several minutes. If the content is streamed from the application server instead of IBM HTTP Server in this case, the downloads cause significant performance problems on the network.

When Content Download HTTP Cache (CDHC) is enabled, IBM FileNet Collaboration Services redirects the content requests for a large file to a dedicated web server with a secure reference to the content in the cache. A dedicated web server streams the content more efficiently and with fewer potential performance problems. In an environment with a WebSphere Application Server deployment, the content requests are redirected to an IBM HTTP Server.

Important: Content that is cached by CDHC is protected by operating system user access controls, but is not encrypted. CDHC should not be used if the IBM FileNet Collaboration Services repository uses encrypted storage areas.

Procedure

To configure IBM FileNet Collaboration Services and the IBM HTTP Server for CDHC:

Configure IBM HTTP Server for CDHC. Follow the instructions for configuring files for production deployments as described here: http://www.lotus.com/ldd/lcwiki.nsf/dx/Configuring_Files_and_Wikis_downloading_for_production_deployments_lc3. Be sure to replace the example statements in the task with the following statements applicable to setting up CDHC for IBM FileNet Collaboration Services.
1. When you create an alias for the data directory root, add the following statement to the httpd.conf file:
```
Alias /alias data_directory_root
```
  where alias is the alias name you are creating and data_directory_root is the root directory to which the alias is referring.
2. Use the following statements after the alias statement in the httpd.conf file to make the alias secure:
```
<Directory "data_directory_root">
Order Deny,Allow
Deny from all
Allow from env=REDIRECT_CDHC_CONTENT
</Directory>
```
  where data_directory_root is the root directory to which the alias is referring.
3. When you add statements to the httpd.conf file to enable the module, use the following statements and add them after the alias statements that are specified previously.
```
<Location application_context_root
 IBMLocalRedirect On 
 IBMLocalRedirectKeepHeaders X-LConn-Auth,Cache-Control,
Content-Type,Content-Disposition,
Last-Modified,ETag,Content-Language,Set-Cookie
 SetEnv CDHC_CONTENT true
</Location>
```
  where application_context_root is the last part of the application URL. For example, the application context root of a Files application with the URL www.my.example.com/dm is /dm.
4. Add the following statement to enable CDHC:
```
RequestHeader append CDHC_ENABLED true
```
Save and close the httpd.conf file.
Share the directory you specified in the IBM HTTP Server httpd.conf file so that both IBM HTTP Server and IBM FileNet Collaboration Services have access to it.

Enable CDHC in IBM FileNet Collaboration Services:

Method Details

Method	Details
Manually edit the site preferences parameters	Edit the following parameters in the fncs-siteprefs.properties file, which is in the configure/explodedformat/fncs/WEB-INF/classes subdirectory of the IBM Content Navigator installation directory: Enable CDHC by setting the cdhc_isEnabled property to `true`. Specify the CDHC root directory by setting the cdhc_rootPath property to a local drive or a network share. The physical location of this directory must be accessible by the IBM HTTP Server server as a network share. This value corresponds to the `data_directory_root` value that you used when you created the alias in the httpd.conf file. For example: `cdhc_rootPath=C:/cdhc` Specify the IBM HTTP Server alias that is used for the root of the CDHC directory by setting the IBM HTTP Server cdhc_urlPath property. The alias is used to point to the cache directory from the IBM FileNet Collaboration Services URL. Specify the alias with the format /`alias`, for example, `/cdhc_content`. When `/cdhc_content` is included in the IBM FileNet Collaboration Services URL, the application is redirected to the fully qualified cache directory. For example: `cdhc_urlPath=/cdhc_content` Specify the HTTP header value that is also specified in the IBM HTTP Server httpd.conf configuration file by setting the cdhc_guardHeader property. The header is used by IBM FileNet Collaboration Services to determine whether the HTTP request is coming from the IBM HTTP Server. CDHC can work only if the request is being forwarded by an IBM HTTP Server. For example: `cdhc_guardHeader=CDHC_ENABLED` The value you enter for the `cdhc_guardHeader` must correspond to the value used in the following statement you added in the httpd.conf file: `RequestHeader append CDHC_ENABLED true`
Use the IBM Content Navigator administration tool	Important: You can use the IBM Content Navigator administration tool to complete this task only if you are entitled to use the IBM Content Navigator administration tool. Enable CDHC for all of the IBM FileNet P8 repositories that are used to store IBM Connections content: Log in to the IBM Content Navigator administration tool. Select FileNet Content Manager. In the Content Download HTTP Cache Configuration section, enable CDHC. In the Fully qualified cache directory field, specify the fully qualified path of the directory where you want to store cached files. The directory can be on any operating system or device, such as a shared network directory, as long as it is visible as a file system to IBM FileNet Collaboration Services and IBM HTTP Server. In the Alias for the cache location field, specify the alias that is used to point to the cache directory from the IBM FileNet Collaboration Services URL. Specify the alias with the format `/alias`, for example, `/cdhc_content`. When `/cdhc_content` is included in a URL, the application is redirected to the fully qualified cache directory. In the HTTP header for gatekeeping field, enter the value that you specified for the RequestHeader in the http.conf file. If a client application does not route a request through IBM HTTP Server, the cached content cannot be downloaded. The HTTP header, which is added to requests from IBM HTTP Server, prevents download failures by ensuring that only requests that are routed through IBM HTTP Server are able to access the cached content. If a request does not have the HTTP header, the content is routed through the web application server rather than IBM HTTP server. Configure any optional parameters to tune CDHC for your environment. Save your changes to the configuration.

Manually edit the site preferences parameters

Edit the following parameters in the fncs-siteprefs.properties file, which is in the configure/explodedformat/fncs/WEB-INF/classes subdirectory of the IBM Content Navigator installation directory:

Enable CDHC by setting the cdhc_isEnabled property to true.
Specify the CDHC root directory by setting the cdhc_rootPath property to a local drive or a network share. The physical location of this directory must be accessible by the IBM HTTP Server server as a network share. This value corresponds to the data_directory_root value that you used when you created the alias in the httpd.conf file.
For example:
```
cdhc_rootPath=C:/cdhc
```
Specify the IBM HTTP Server alias that is used for the root of the CDHC directory by setting the IBM HTTP Server cdhc_urlPath property.
The alias is used to point to the cache directory from the IBM FileNet Collaboration Services URL. Specify the alias with the format /alias, for example, /cdhc_content. When /cdhc_content is included in the IBM FileNet Collaboration Services URL, the application is redirected to the fully qualified cache directory.
For example:
```
cdhc_urlPath=/cdhc_content
```
Specify the HTTP header value that is also specified in the IBM HTTP Server httpd.conf configuration file by setting the cdhc_guardHeader property.
The header is used by IBM FileNet Collaboration Services to determine whether the HTTP request is coming from the IBM HTTP Server. CDHC can work only if the request is being forwarded by an IBM HTTP Server.
For example:
```
cdhc_guardHeader=CDHC_ENABLED
```
The value you enter for the cdhc_guardHeader must correspond to the value used in the following statement you added in the httpd.conf file:
```
RequestHeader append CDHC_ENABLED 
true
```

Use the IBM Content Navigator administration tool

Important: You can use the IBM Content Navigator administration tool to complete this task only if you are entitled to use the IBM Content Navigator administration tool.

Enable CDHC for all of the IBM FileNet P8 repositories that are used to store IBM Connections content:

Log in to the IBM Content Navigator administration tool.
Select FileNet Content Manager.
In the Content Download HTTP Cache Configuration section, enable CDHC.
In the Fully qualified cache directory field, specify the fully qualified path of the directory where you want to store cached files.
The directory can be on any operating system or device, such as a shared network directory, as long as it is visible as a file system to IBM FileNet Collaboration Services and IBM HTTP Server.
In the Alias for the cache location field, specify the alias that is used to point to the cache directory from the IBM FileNet Collaboration Services URL.
Specify the alias with the format /alias, for example, /cdhc_content. When /cdhc_content is included in a URL, the application is redirected to the fully qualified cache directory.
In the HTTP header for gatekeeping field, enter the value that you specified for the RequestHeader in the http.conf file.
If a client application does not route a request through IBM HTTP Server, the cached content cannot be downloaded. The HTTP header, which is added to requests from IBM HTTP Server, prevents download failures by ensuring that only requests that are routed through IBM HTTP Server are able to access the cached content.

If a request does not have the HTTP header, the content is routed through the web application server rather than IBM HTTP server.
Configure any optional parameters to tune CDHC for your environment.
Save your changes to the configuration.

Restart the IBM FileNet Collaboration Services application in WebSphere Application Server for the fncs-siteprefs.properties file updates to take effect.