Citrix XenApp server uses server farms to organize and manage servers. This allows you to manage any settings as a unit rather than apply them individually
each machine. Servers in a farm all connect to the same datastore and generally have some features in common that make grouping them together logical. Farms also provide a method for application
publishing. Publishing an application means to provide it to remote users from the server installation. Within the farm model are the two technologies that make the on-demand enterprise function: Independent Management Architecture (IMA) and Independent Computing Architecture (ICA).
each machine. Servers in a farm all connect to the same datastore and generally have some features in common that make grouping them together logical. Farms also provide a method for application
publishing. Publishing an application means to provide it to remote users from the server installation. Within the farm model are the two technologies that make the on-demand enterprise function: Independent Management Architecture (IMA) and Independent Computing Architecture (ICA).
XenApp Server Farms
Users and administrators alike quickly realize the value of a Citrix XenApp server in delivering applications for a variety of needs. However, it does not take long for one of these servers to reach its capacity. Administrators then bring other Citrix servers online to provide the needs for the new users. The problem seems to be solved; yet as new servers are added to the network, another issue arises: It becomes increasingly complex for users to determine which server to use. In addition, administrators are faced with having to install multiple servers with a variety of applications, configuring sessions and users, and managing them. Server farms simplify these issues. When a server farm is constructed, administrators can manage the entire set of Citrix XenApp servers from a single point. Printer drivers and applications can be easily deployed to all the servers at once
Users can connect directly to applications, without needing to know the location of an individual server.
Citrix XenApp 5.0 Server—in particular, the Platinum and Enterprise versions was intended for a scalable server farm. Not only does it load balanceuser sessions across multiple servers and provide redundancy, but it also provides easy administration capabilities. The first step toward installing a Citrix XenApp server farm involves understanding and designing one that will scale up with the network over time. Proper planning and project management can play a critical rolein the success of your implementation. In addition, administrators must be capableof managing the farm after the installation to ensure that it remains reliable.
A server “farm” is typically a collection of servers that provide a similar service or function. The collection provides increased computing power over a single large system as well as a level of redundancy not usually available in any single PC-based server installation. The farm provides operating system (OS) redundancy. Servers can provide processor, hard disk, power supply, and disk controller redundancy but very little in the
OS area. By farming like servers, even if the OS crashes, customers are still served. The customer might lose the current session when a server crashes, but he or she can immediately reconnect to another server and receive the same environment as before. Windows 2003 Terminal Services can be placed into a physical farm and set to be accessed by methods such as Windows Load Balancing (WLB) or Domain Name Service (DNS) round robin. These methods are not truly load balanced, nor can the entire farm be managed as a single entity. WLB does not allow for all the metrics to be taken into consideration in determining the least busy server. DNS round robin could provide the address of a server that is offline, resulting in attempted connections to a server that is not available.
By adding Citrix XenApp server to Windows 2003 Terminal Service, server farms can be managed from a single interface and provide redundancy and better load-balancing services to users. XenApp server also allows administrators to take advantage of features such as published applications, client or server sidestreamed applications, seamless windows, content redirection, multiple-platform clients, the Citrix Web
Interface, Secure Gateway, and local drive and printer access. A single-server farm can span an entire enterprise or can be broken up into smaller farms for localized management or Disaster Recovery. This flexibility allows administrators to choose to centralize licensing and management by creating a single corporate farm or to distribute licensing and management to regional or departmental administrators.
