NetScaler – Server offload – AppCache
A basic intro to App Cache on NetScaler… hundreds of use cases but the principles are the same.
NetScaler AppCache – or Application caching is a very simple way of massively reducing server workloads by removing the need to repeatedly generate common content.
Traditionally, servers provide content for each individual user as demanded. As a typical example, When 50 users wish to visit a website, then the web servers must generate the homepage from scratch 50 times – once for each user. Taking a snapshot of the homepage, and holding the content on a NetScaler appliance with the App Cache feature* allows the homepage to be delivered directly from the NetScaler appliance.
Taking this repetitive workload off the server frees up computational resource, leaving more capacity to deliver specific requests for less popular content and ultimately more users per server and as an additional benefit the content can be delivered quicker to improve the end user experience.
This cache can be pre-populated or policies set to allow the NetScaler to take a snapshot on the fly if a piece of content becomes unexpectedly popular with the Action Analytics feature released this year (see Action Analytics post). Typical production deployments will cache both full pages and component parts of more dynamic content such as the branding and templates in a SharePoint screen -Al
*AppCache is included in the Platinum Edition MPX & VPX appliances and available as a stand alone option for the MPX platforms. As an indication of the popularity of this feature, the newly released 8000 series chassis support up to 32GB of cache content for huge potential offload benefit
© Al Taylor 25th Sept 2012