This check determines whether there are servers in the environment with binary large object (BLOB) caching enabled.
BLOB caching can be enabled on web servers that accept and process end-user requests. Before you enable BLOB caching, carefully consider how you plan to use it. In some scenarios, like in a heavy collaboration, a BLOB cache can even lower performance due to the intensive caching operations. A BLOB cache has a high benefit in the following scenarios:
Publishing sites hosting a lot of static content and image renditions,
Sites with a large number of read-only media files or where only a small percentage of the media assets are updated.
There is one BLOB cache per web application. Consider choosing a dedicated drive as the cache location. Storing cache files on the same drive as SharePoint binaries, page files or ULS and IIS logs can have a negative impact on the performance of the system.
BLOB caching is enabled by editing the web.config file for the web application and changing the following line:
BlobCache location="C:BlobCache14"path=".(gif|jpg|jpeg|jpe|jfif|bmp|dib|tif|tiff|themedbmp|themedcss|themedg if|themedjpg|themedpng|ico|png|wdp|hdp|css|js|asf|avi|flv|m4v|mov|mp3|mp4|m|mpg|rm|rmvb|wma|wmv|ogg|ogv|oga|webm|xap)$" maxSize="10"enabled="false"
You can find extensive information about the configuration of and planning for BLOB caching in the article specified under Additional information.
Additional information can be found in the following TechNet article: