Event ID 353 — Cache/Proxy Directory Availability

Applies To: Windows Server 2008

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.

Event Details

Diagnose

This error is caused by one of the following conditions:

• The cache directory on the cache/proxy server is full.
• The origin server is either not available or too busy to process the cache download request.

The cache directory on the cache/proxy server is full

To determine whether the cache directory is full:

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 Cache tab, note the cache directory path value in Cache Directory Path. The default value is %systemdrive%\WMSCache.
7. In the Cache Settings area, note the values for the following options that specify how much space is available for cached file storage in the cache folder:
   • Limit Disk Quota (MB). The amount of space in the cache folder for storing on-demand files.
   • Limit Archive Quota per Stream (MB). The amount of space available in the cache folder for storing a single on-demand file that is created from a live stream by the Play While Archiving feature.
8. In Windows Explorer, open the cache folder, and then determine how much space is consumed by the cached files.
9. If the total amount of disk space consumed by the files in cache folder is nearing either of the specified quota limits, see the section titled "Make disk space available for cache file storage."

The origin server is either not available or too busy to process the cache download request

To determine origin server availability:

1. Use the Ping command to test the local area network (LAN) connection to the origin server.
2. If you can connect to the origin server, diagnose potential bandwidth bottleneck issues on the network. For more information, see Bandwidth.

For more information about resolving this issue, see the section titled "Optimize streaming media network availability."

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

Make disk space available for cache file storage

There are several methods available to you for making additional storage space available for cached files on the cache/proxy server. Possible resolutions include:

• Change the disk space storage limit for the cache directory.
• Remove cached files from the cache directory.
• Change the cache directory to another location that has sufficient disk space.

Change the disk space storage limit for the cache directory

To change the disk space storage limit for 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 Cache tab, in Cache Settings, use one of the following procedures:
   • If you are storing on-demand content files in the cache directory, select the Limit Disk Quota (MB) check box and then specify a higher capacity value for storing cached files.
   • If you are storing a single on-demand file that is created from a live stream by the Play While Archiving feature in the cache directory, select the Limit Archive Quota per Stream (MB) check box and then specify a higher capacity value for storing the cached file.

Remove files from the cache directory

To remove files from 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, use one of the following procedures:
   • On the Cache tab, click Clear Cache to remove all files stored in the cache directory.
   • On the Query tab, search for files in the cache directory to remove, and then click Delete to remove the files from the results list.

Note: Cached content actively being streamed by clients is marked for deletion and is deleted when the last user session ends. If another client requests cached content that has been marked for deletion or has been deleted, the cache/proxy server will download another copy of the content from the origin server to fulfill the request.

Change the cache directory

To change 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 Cache tab, in Cache Settings, click Browse to select another cache directory.

Optimize streaming media network availability

If the cache/proxy server cannot connect to the origin server on the network, resolve any problems with the network adapter. (For more information, see Troubleshooting network and dial-up connections.) If the network is functioning normally, investigate and resolve potential bandwidth bottleneck issues on the network. (For more information, see Bandwidth.) If the network is tuned correctly, try restricting the cache download caching speed on the cache/proxy server to the available bandwidth.

To restrict the cache download caching speed to the available bandwidth:

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, in Caching Speed, select the Maximum Available Bandwidth option to allow caching of content from the origin server as fast as the network will allow.
7. Click OK to save the changes.

Note: If the network is operating near maximum capacity, the cache download speed may still be slow. A streaming media network that has been correctly planned and configured will improve response time, data throughput, content availability, and reduce the data error rate. To estimate the server requirements that you must have to ensure that your content can reach all your clients without delays or interruptions, see Capacity planning. To test the capacity of your Windows Media server, you can simulate client requests for unicast streams from the server by using Microsoft Windows Media Load Simulator.

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 Directory Availability

Streaming Media Services