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Proxy Performance

There might be occasions when you encounter performance issues with your Web Gateway. This can be to due to a number of causes and can include:

• High volumes of web traffic
• Excessive number of users on (or requests to) the Web Gateway
• Content scanning engines having difficulty processing particular URLs

Your Web Gateway has a number of features that allow you monitor and manage proxy performance:

• The Proxy Monitoring page allows you to configure proxy logging files and create diagnostic outputs.
• The Watchdog features enable you identify issues with the proxy server and resolve them automatically or, if preferred, generate warning messages to prompt for manual investigation.
• The features on the Proxy Status tab on the Health page allow you to monitor the activity of the content scanning engines, and restart problem engines as required.

Tell me about...

• The Proxy Monitoring Page

  The Proxy Monitoring page offers a number of features that allow you to investigate proxy issues by means of logging and diagnostic reports:

  • Proxy Diagnostic Ports

    This feature allows you to generate low-level diagnostic messages that describe proxy and engine actions that the Web Gateway is performing. They provide more detail than log files and you would normally use the feature on the advice of Clearswift support personnel when resolving complex proxy issues. You are able to:

    • Examine how the engine has modified the raw content of an HTTP response. For example, you could use the engine diagnostics to see how the Gateway has modified the response it has received from a Web server to comply with the needs of the organisation's acceptable use policy.
    • Examine the request/response mechanism for a given URL. For example, if a user reports an unexpected response when attempting to browse a page, you can use proxy diagnostics to see the precise HTTP transaction that took place.

  • Proxy Log Level

    You use this feature to configure the level of detail that is included in Gateway logs. You can also include specialized logging features such as Event Signaling and Engine Bypass.

  • Proxy Request Logging

    Proxy Request Logging allows you to log all requests and responses processed by the proxy including data exchanged between the client and the proxy and the proxy and the server. Use this logging feature to investigate problems that occur when accessing a particular URL.

  • Cache Diagnostics

    Use Cache Diagnostics to add x-header debugging and generate log cache events.

  The Proxy Monitoring page also contains the user interface for the Content Scanning Engine and Proxy Watchdog. Due to the nature of these features, they are described separately.

• The Watchdogs

  There are two Watchdogs.

  • The Content Scanning Engine Watchdog monitors content scanning engines, and will generate alarms and restart problem engines as appropriate.
  • The Proxy Watchdog monitors the proxy to ensure it is active, and will generate alarms and restart the proxy as appropriate.

  Both Watchdogs can be configured to work in different modes of operation. You can:

  • Choose to detect if there is a problem with engines or the proxy automatically, thereby allowing you to ‘switch off’ the feature
  • On detection of a problem engine or inactive proxy, raise an alarm
  • On detection of a problem engine or inactive proxy, restart the engine and raise an alarm
• Proxy Status

  Proxy Status allows you to check the status of the proxy and proxy engines by means of a User Interface in the Web Gateway. It is useful in general monitoring of the proxy and in helping with problem diagnosis. For example, in the situation where a content scanning engine is stuck due to the processing of a particular URL, you can identify the URL and client for further investigation. In addition, the feature provides a mechanism for recovering content scanning engines that are stuck by allowing you to selectively restart them.

• The best method to adopt to monitor the proxy

  If you want an immediate view and want to be able to restart a proxy or individual proxy engines, you should use Proxy Status and the Proxy Watchdog features. You can only restart the content scanning engines by using Proxy Status .

  Proxy Status and Watchdogs

  By combining Proxy Status and the Proxy Watchdog features, you are able to monitor and manage both proxy and proxy content scanning engine processes.

  Proxy Status provides a detailed status of the proxy and content scanning engines, and you are able to restart engines from this page. However, if you only use this method, you will need to monitor the Proxy Status on a regular basis as problem engines will not be started automatically.

  The Content Scanning Engine Watchdog allows automatic identification and resolution of engines that have failed to process a URL. If the Watchdog has been configured to provide a warning only, you can use Proxy Status to investigate the issue and manually restart the engine if appropriate.

  Even if the Content Scanning Engine Watchdog is configured to restart engines automatically, you can resolve issues with problem engines sooner by performing a manual restart from Proxy Status .

  The Proxy Watchdog is similar to the Content Scanning Engine Watchdog in terms of the actions performed when the Watchdog has detected that the proxy is not active. That is, off (perform no action), generate alarm only, or generate alarm and automatic restart.

  Note that all watchdog activity is logged.

  We recommend that you configure both watchdogs to detect and resolve problems automatically. Use Proxy Status for when you want to check engine processes, or manually resolve reported problems.

How do I...

• Work with the features on the Proxy Monitoring Page?

  We recommend that you use these features only under the guidance of Clearswift support personnel.

  For further detail on these features, select the appropriate link:

  • Work with Proxy Diagnostic Ports to gather diagnostic messages
  • Configure the level of log detail with Proxy Diagnostic Log Level
  • Log and then analyze proxy requests and responses with Proxy Request Logging
  • Set and examine Cache Diagnostics
  • Work with the Watchdogs
• Work with the Watchdogs?

  The user interface for the watchdogs is found on the Watchdog tab on the Proxy Monitoring page.

  For further detail on this page, including steps on how to configure the feature, see the Proxy Watchdogs topic.

• Work with Proxy Status?

  The User Interface for Proxy Status is found on the Proxy Status tab on the Health home page.

  For further detail about this page, including working with suspected problem URLs, and restarting engines, see the Proxy Status topic.

See also...

• Monitoring and Managing your Gateway for an overview of system performance tools