Manual Chapter : Accelerating Responses with Metadata Cache Responses

Applies To:

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BIG-IP AAM

  • 14.1.3, 13.1.5, 13.1.4, 13.1.3, 13.1.1, 13.1.0, 13.0.1, 13.0.0

BIG-IP APM

  • 14.1.3, 14.1.2, 14.0.1, 14.0.0, 13.1.5, 13.1.4, 13.1.3, 13.1.1, 13.1.0, 13.0.1, 13.0.0
Manual Chapter

Overview: Using Metadata cache responses to accelerate responses

Responses from origin web servers include entity tags (ETags), which are arbitrary strings attached to a document that specify some characteristic of the document, such as a version, serial number, or checksum of content. A changed document includes a different ETag, enabling a client's GET request to use an If-None-Match conditional header to acquire a new copy of the document. Because not all web applications generate ETags consistently, the BIG-IP device creates its own ETag for each cached document that is based on a signature, or checksum, of the document's content. The BIG-IP device stores content signatures in the Metadata cache for other optimizations, including Intelligent Browser Referencing.

BIG-IP applications provide options to always or never send metadata. All BIG-IP applications share the same Metadata cache.

BIG-IP policies cache ETag headers, which include the following:

  • Request URL
  • Content signature of the response body
  • Application name for the matching request
  • Metadata, including the expiration time, read time, and update time for content

Accelerating Metadata responses

The BIG-IP system creates its own Metadata response for each cached document that is based on a signature, or checksum, of the document's content. The BIG-IP system stores content signatures in the Metadata cache for other optimizations, including Intelligent Browser Referencing.
  1. On the Main tab, click Acceleration > Web Application > Applications .
    The Applications List screen opens.
  2. Click the name of an application.
  3. From the General Options list, select Advanced.
  4. From the Send Metadata list, select Always.
  5. In the Metadata Cache Max Size field, type a size in megabytes (MB) for the maximum cache size.
  6. Click Save.
The BIG-IP system stores content signatures in the Metadata cache.

Disabling Metadata responses

If necessary, you can disable the BIG-IP system from sending Metadata responses.
  1. On the Main tab, click Acceleration > Web Application > Applications .
    The Applications List screen opens.
  2. Click the name of an application.
  3. From the General Options list, select Advanced.
  4. From the Send Metadata list, select Never.
  5. Click Save.
The BIG-IP system no longer sends Metadata responses.