Manual Chapter : Accelerating Responses with Metadata Cache Responses

Applies To:

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  • 11.5.10, 11.5.9, 11.5.8, 11.5.7, 11.5.6, 11.5.5, 11.5.4, 11.5.3, 11.5.2, 11.5.1
Manual Chapter

Accelerating Responses with Metadata Cache Responses

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. Additionally, you can specify a maximum size for the Metadata cache, in megabytes. 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

Advanced Metadata Cache Options for General Options

For the General Options list, this table describes the Advanced settings and strings for Metadata Cache Options.

Advanced control Default Description
Send Metadata Always This setting determines whether and how the BIG-IP performs Metadata caching for responses.
  • Never. The BIG-IP does not cache Metadata headers.
  • Always. The BIG-IP always caches Metadata headers before sending them to a client.
Metadata Cache Max Size 25 Specifies the size in megabytes (MB) for the maximum Metadata cache size.