Event ID 355 — Cache/Proxy Database Availability

Updated: August 14, 2009

Applies To: Windows Server 2008 R2

red

When a client requests on-demand content, a cache/proxy server can stream the requested content to the client on behalf of the origin server. Offsetting the load on the origin server from which the content is published conserves bandwidth and decreases network-imposed latency, reducing costs and providing a better viewing experience for clients. The WMS Cache/Proxy plug-in in Windows Media Services 2008 is used to configure a Windows Media server as a cache/proxy server. This plug-in downloads content requested by clients from an origin server to cache storage on the cache/proxy server (the cache directory) for subsequent delivery to clients. A record of each downloaded file is maintained in a cache index file (the cache database) so that the plug-in can be used to manage the cache directory.

Event Details

Product: Windows Media Services
ID: 355
Source: WMServer
Version: 9.6
Symbolic Name: WMS_EVMSG_CACHE_INDEX_OPEN_FAILED
Message: The WMS Cache Proxy plug-in could not open the cache database index %1. %2

Diagnose

This error is caused by one of the following conditions:

  • The Network Service account does not have appropriate permissions for the cache directory on the cache/proxy server.
  • The cache index file on the cache/proxy server is missing.

The Network Service account does not have appropriate permissions for the cache directory on the cache/proxy server

To determine the Network Service account permissions for the cache directory:

  1. On the Windows Media cache/proxy server, open Windows Media Services. To open Windows Media Services, click Start, point to Administrative Tools, and then click Windows Media Services.
  2. In the console tree, click the Windows Media server for which you want to cache content.
  3. In the details pane, click the Properties tab.
  4. In Category, click Cache/Proxy Management.
  5. In Plug-in, right-click WMS Cache Proxy, and then click Properties.
  6. In the WMS Cache Proxy Properties dialog box, on the Cache tab, note the cache directory path value in Cache Directory Path. The default value is %systemdrive%\WMSCache.
  7. In Windows Explorer, right-click the cache folder, and then click Properties.
  8. On the Security tab, in the Group or user names area, click NETWORK SERVICE.
  9. In the Permissions for NETWORK SERVICE area, view the permissions allowed for the Network Service account.
  10. If the Network Service account does not have Read, Write, and Modify permissions to the cache directory, see the section titled "Specify Network Service account permissions for caching."

The cache index file on the cache/proxy server is missing

To determine whether the cache index file is missing:

  1. On the Windows Media cache/proxy server, open Windows Media Services. To open Windows Media Services, click Start, point to Administrative Tools, and then click Windows Media Services.
  2. In the console tree, click the Windows Media server for which you want to cache content.
  3. In the details pane, click the Properties tab.
  4. In Category, click Cache/Proxy Management.
  5. In Plug-in, right-click WMS Cache Proxy, and then click Properties.
  6. In the WMS Cache Proxy Properties dialog box, on the Cache tab, note the cache directory path value in Cache Directory Path. The default value is %systemdrive%\WMSCache.
  7. In Windows Explorer, open the cache folder.
  8. If the cache index file named CacheIndex.txt is not present in the cache folder, see the section titled "Create a new cache index file."

Resolve

To resolve this issue, use the resolution that corresponds to the cause you identified in the Diagnose section. After performing the resolution, see the Verify section to confirm that the feature is operating properly

Cause

Resolution

The Network Service account does not have appropriate permissions for the cache directory on the cache/proxy server

Specify Network Service account permissions for caching

The cache index file on the cache/proxy server is missing

Create a new cache index file

Specify Network Service account permissions for caching

Windows Media Services uses the Network Service account to manage the content files that are cached in %systemdrive%\WMSCache and its subdirectories on the cache/proxy server. By default, the Network Service account has Read, Write, and Modify permissions to the WMSCache directory and its subdirectories.

If the specified cache folder does not reside in %systemdrive%\WMSCache, you must specify permissions on the alternate cache folder for the Network Service account on the cache/proxy server.

To perform this procedure, you must have membership in the local Administrators group, or you must have been delegated the appropriate authority.

To specify Network Service account permissions for caching:

  1. On the Windows Media cache/proxy server, open Windows Media Services. To open Windows Media Services, click Start, point to Administrative Tools, and then click Windows Media Services.
  2. In the console tree, click the Windows Media server for which you want to cache content.
  3. In the details pane, click the Properties tab.
  4. In Category, click Cache/Proxy Management.
  5. In Plug-in, right-click WMS Cache Proxy, and then click Properties.
  6. In the WMS Cache Proxy Properties dialog box, on the Cache tab, note the cache directory path value in Cache Directory Path. The default value is %systemdrive%\WMSCache.
  7. In Windows Explorer, right-click the cache folder, and then click Properties.
  8. On the Security tab, click Edit.
  9. In the Permissions for <Object name> dialog box, click Add.
  10. In the Select Users, Computers, or Groups dialog box, in Enter the object names to select, type Network Service, and then click OK.
  11. In the Permissions for <Object name> dialog box, in the Group or user names area, click NETWORK SERVICE.
  12. In the Permissions for NETWORK SERVICE area, click the Allow check box for the following permissions: Read, Write, Modify.
  13. Click OK to save the changes.

Create a new cache index file

To create a new cache index file, you must empty the cache directory on the cache/proxy server. The next time a client requests content, the cache/proxy server will download the requested content from the origin server and create a new cache index file that includes an entry for the content.

To perform this procedure, you must have membership in the local Administrators group, or you must have been delegated the appropriate authority.

To empty the cache directory:

  1. On the Windows Media cache/proxy server, open Windows Media Services. To open Windows Media Services, click Start, point to Administrative Tools, and then click Windows Media Services.
  2. In the console tree, click the Windows Media server for which you want to cache content.
  3. In the details pane, click the Properties tab.
  4. In Category, click Cache/Proxy Management.
  5. In Plug-in, right-click WMS Cache Proxy, and then click Properties.
  6. In the WMS Cache Proxy Properties dialog box, on the Cache tab, note the cache directory path value in Cache Directory Path. The default value is %systemdrive%\WMSCache.
  7. In Windows Explorer, open the cache folder.
  8. Select all files and folders in the cache folder, and then delete them.

Verify

To verify that cache/proxy servers on your network can cache content files from the origin server, prestuff the cache directory on the cache/proxy servers with one or more content files from the origin server. Prestuffing content means that you are caching the content on the cache/proxy servers before it is requested by clients. It is a good way to confirm that cache/proxy servers on your network can communicate with the origin server.

To prestuff the cache directory:

  1. On the Windows Media server, open Windows Media Services. To open Windows Media Services, click Start, point to Administrative Tools, and then click Windows Media Services.
  2. In the console tree, click the Windows Media server for which you are caching content files.
  3. In the details pane, click the Properties tab.
  4. In Category, click Cache/Proxy Management.
  5. In Plug-in, right-click WMS Cache Proxy, and then click Properties.
  6. In the WMS Cache Proxy Properties dialog box, on the Prestuff tab, use one of the following procedures:
    • Prestuff from Stream. Select this option to enable the cache/proxy server to cache the content by streaming it from the origin server. Type the URL of the file on the origin server in the URL box and select one of the Prestuff Rate options to specify the speed at which the cache/proxy server streams the content from the origin server.
    • Prestuff from File. Select this option to enable the cache proxy server to cache the content from a file on an available file storage system, such as a local file system, storage area network (SAN), or network-attached storage (NAS). Type the UNC path of the file in the Content Path box, the URL that clients must use to stream the file in the Stream URL box, and then select the Copy content to local cache directory check box.
  7. Click Prestuff to start caching the specified content from the origin server. If caching is configured correctly on the cache/proxy server, the content file will appear in the cache directory after a short delay.

Related Management Information

Cache/Proxy Database Availability

Streaming Media Services

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