Product Documentation

Deciding How Many Farms to Deploy

Oct 09, 2015
Most organizations deploy a single farm. However, there are some circumstances in which deploying multiple farms makes sense. The decision to implement a single farm or multiple farms is influenced by:
  • Location and needs of the users or your organization - If your organization is a service provider, you might want to dedicate a farm to each organization for which you provide service. Multiple farms might make it easier to demonstrate compliance with specific service level agreements.
  • Geographic layout of your organization - If your IT infrastructure is organized by region and managed in a decentralized manner, multiple farms could improve farm performance. Multiple farms could also save time when coordinating farm administration and simplify troubleshooting farm-wide issues.
  • Network infrastructure limitations - In WANs with high latency or error rates, multiple farms may perform better than a single farm with multiple zones.
  • Organizational security policies concerning server communications - Consider multiple farms if your organization needs to segregate data based on security level. Likewise, you might need multiple farms for regulatory compliance.
  • Application deployment methods - If you plan to use Microsoft System Center Configuration Manager 2007 R2 to deploy applications, XenApp Connector for System Center Configuration Manager 2007 R2 components must be installed on servers within the same farm.
There is no exact formula for determining the ideal number of farms, but general guidelines can help:
  • In general, a single farm meets the needs of most deployments. A significant benefit to deploying a single farm is needing only one data store database.
  • Consider using multiple farms when you have geographically dispersed data centers that can support their own data store database, or when you do not want communication between servers within the farm to cross a firewall or WAN. For very large deployments with thousands of servers, breaking the environment into multiple farms can increase performance.

Citrix regularly tests farm scalability based on 1000-server farms.

Farm Element or Component Single Farm Multiple Farms
Data Store The farm has one data store. Each farm must have a data store.
Data Store Replication Citrix recommends that you replicate the data store to remote sites when using one farm in a WAN environment. If each remote site is a farm with its own data store, there is no need for data store replication.
Load Balancing You can load balance an application across the farm. You cannot load balance an application across servers in different farms.
Firewall Traversal If the farm spans multiple sites, firewall ports must be open for server-to-server communication. Site-based farms eliminate the need to open firewall ports for server-to-server communication.
Server-to-server Communication Data store information is synchronized with member servers through notifications and queries. When a farm has multiple zones, data collectors communicate dynamic information such as logons and application use across the farm. Multiple farms might improve performance over a single farm when server-to-server traffic crosses a WAN link or when the farm is very large.
Management Tools You can monitor and configure the farm from a single management console and need to log on to only one farm to do so. You can monitor and configure multiple farms from management console. Communicating with multiple farms from the console requires logging on to each farm.

Sharing Components Between Farms

Some Citrix components can be shared between multiple farms; consequently, it is not necessary to consolidate all servers in one farm to prevent deploying these components multiple times:
  • Web Interface - Sharing Web Interface between farms provides central access to applications published on different farms.
  • SmartAuditor - With the exception of the SmartAuditor Agent, all components are independent of the server farm. For example, you can configure multiple farms to use a single SmartAuditor Server.
  • Citrix Licensing - You can manage multiple farms using one Citrix License Server; however, performance might be affected if you use only one license server for all servers in a WAN.
  • EdgeSight - You can use EdgeSight and Resource Manager powered by EdgeSight to monitor multiple farms. Note that servers running Presentation Servers 4.5 agents appear as endpoints.