Manage Cache Hierarchy Using ARR
Applies To: Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Vista
This topic describes how to configure Application Request Routing (ARR) as an edge cache node in a cache hierarchy using the Cache Array Routing Protocol (CARP). ARR uses the concept of server farms to define the logical relationship between member servers, such as a group of application servers or a group of cache nodes. When server farms are used in a hierarchy, the group of cache nodes is the next tier in the architecture where incoming requests should be routed when there is a cache miss.
You should be familiar with and have the disk-based cache feature configured before you continue. For more information, see Configure and Enable Disk Cache in ARR.
For information about how to configure ARR in a typical two-tier cache node environment for content delivery networks (CDN) and edge caching networks (ECN), see Deploy Application Request Routing in CDN.
To manage cache hierarchy using ARR, you must complete the following procedures:
Define the cache hierarchy.
Enable CARP.
Define the Cache Hierarchy
To define the cache hierarchy, you must create and define a server farm with the parent cache nodes as its members.
To define the cache hierarchy
Open IIS Manager.
In the Connections pane, expand the server node. This is your child (edge) cache node.
To create a server farm, right-click Server Farms, and then click Create Server Farm….
In the Create Server Farm wizard, on the Specify Server Farm Name page, enter a name for your server farm in the Server farm name box. Click Next.
On the Add Server page, enter the server addresses for the parent cache nodes that you want to add to your server farm. When there is a cache miss at the child node, the requests will use CARP to route to one of the parent cache nodes. Click Finish.
The URL rewrite module inspects incoming HTTP requests and server variables, and makes routing decisions. To create the default URL rewrite rules for your server farm, click Yes in the confirmation dialog box.
Enable CARP
ARR includes support for CARP, which is used to determine which parent cache node to forward a request to when there is a cache miss at the child cache node.
To enable CARP
Open IIS Manager.
In the Connections pane, expand the server node and then expand the Server Farms node. Select the server farm that you just created.
In the Server Farm pane, double-click Load Balance.
On the Load Balance page, select Request hash from the Load balance algorithm list.
Click Apply.