Applies To:Show Versions
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.
|Send Metadata||Always||This setting determines whether and how the BIG-IP performs Metadata
caching for responses.
|Metadata Cache Max Size||25||Specifies the size in megabytes (MB) for the maximum Metadata cache size.|