About Cherwell Server Farms

A server farm allows high volumes of Users to utilize several medium (4-core or higher) servers. A server farm consists of multiple CSM servers connecting to multiple Redis Servers.

Using multiple servers allows for:

  • A level-of-fault tolerance.
  • Individual servers to also be taken offline without impact to users.
  • Operating system and hardware maintenance without reducing User availability.
Services that are not load balanced should not be installed on more than one machine. Set up another single-server connection for services that cannot be load balanced.

There is near-linear growth using Cherwell Server Farms. The more servers added to the farm, the more Users CSM servers can support. For example, assuming identical hardware is used: If Users are consuming 100 percent of CPU on a single server, create a farm with three servers in order to support more Users. If two servers support 100 Users, then three servers can support 150 Users.

Important: Using the Cherwell Server Farm can increase the stress on SQL Server, the load balancer, and Redis Server. When creating a Cherwell Server Farm, it is imperative to consider the impact of an increased load on the entire infrastructure. Do not simply add servers without considering the impact.

Specific Requirements

  • CSM must be installed as an IIS service, not a Windows service.
  • Windows IIS features HTTP Activations and non-http activations must be installed. See Configure IIS for CSM.
  • Machine keys must be generated in IIS on one CSM server and copied to IIS on all CSM servers in the Cherwell Server Farm. See Configuring Server Farms in IIS.
  • Session pinning is not supported.