Cache settings operations in SharePoint Server

SharePoint Server provides four types of caches that help improve the speed at which web pages load in the browser:

1. BLOB cache

2. Page output cache

3. Object cache

4. Anonymous search results cache

The BLOB cache is enabled and configured in the Web.config file in the web application to which you want to apply the cache. The page output cache and object cache are usually configured in the user interface at the site collection level. Certain settings for these caches can also be configured at the web application level. The changes that you make to the Web.config file will be applied to all site collections and sites within the web application, and will supersede any configuration made at the site collection level or below.

Note : To use the page output cache or the object cache, you must be using the Publishing feature on your site.

BLOB cache

SharePoint Server provides a disk-based cache that stores files that are used by web pages to help them load quickly in the browser, and reduces the load on the database server when it uses those files. These files are known as binary large objects (BLOBs), and the cache is known as the BLOB cache. The BLOB cache is stored directly on the hard disk drive of a front-end web server computer. The first time that a web page is called, these files are copied from the database to the cache on the server hard disk drive, and all subsequent requests for those files are then served from the hard disk drive cache of the server. By default, the BLOB cache is off and must be enabled to use the functionality it provides. When you enable the BLOB cache on your front-end web server, you reduce the load on the SharePoint Server database server created by read requests from web browsers.

Page output cache profiles

The page output cache stores the rendered output of a page. It also stores different versions of the cached page, based on the permissions of the users who are requesting the page. Page output cache settings can be configured at the site collection level, at the site level, and for page layouts. By default, the page output cache is turned off. The page output cache uses cache profiles that specify how long items should be held in the cache. You can specify different cache profiles to be used for anonymous and authenticated users, which optimizes the use of the cache based on the authentication methods that are allowed on the site. You can configure cache profile settings for a web application by editing the Web.config file on the application server. The cache profile settings that you configure at the web application level will be used for all cache profiles in the site collections for that web application.

Object cache

The object cache reduces the amount of traffic between the web server and the SQL database by storing objects - such as lists and libraries, site settings, and page layouts - in memory on the front-end web server computer. As a result, the pages that require these items can be rendered quickly, increasing the speed with which pages are delivered to the client browser. Object cache settings can be configured at the web application level, and at the site collection level. By default, the object cache is on at the site collection level. You can optimize the object cache for a web application by specifying the size of the object cache. Specifying a larger number can enhance performance for some large sites at the cost of memory on each front-end web server. You can configure other settings for the object cache at site collection level.

Anonymous search results cache

The anonymous search results cache is primarily used by publishing sites that allow access to anonymous users. It saves search results from anonymous users and reuses them for later queries that are the same as the original query. This improves performance on site pages that use the Content Search Web Part.