Certification Objective 3.03: Designing a Server Farm

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When preparing to implement Citrix MetaFrame XP, a complete server farm design can mean the difference between a failed implementation and a complete success. Critical issues such as how many farms will be used, network connectivity, how zones will be used, and the data store must be meticulously planned to properly prepare for an installation. Once the business requirements and project analysis are complete, a design can be compiled taking into account each of these items. Within this section, the most critical components will be discussed, including single versus multiple farms, zone designs, and data store issues.

Single Farm

The most common implementation of Citrix MetaFrame XP is using a single server farm. Single farms can be used in both small businesses and large enterprises, due to the increased scalability and reliability. Factors such as database performance, hardware platforms, and network connectivity all play a role in deciding upon using a single farm.

Benefits of using a single farm include:

  • Centralized administration

  • Minimized administrative overhead

  • Pooled licensing

Multiple Farms

Based upon the business requirements of organizations, some implementations require the use of multiple farms. Although this adds an additional level of complexity to an environment, it also comes with its own set of benefits. These benefits include:

  • Decentralized administration

  • Minimized network traffic

  • Minimized security risks associated with network traffic and traversal of firewalls for intra-farm communication

  • Data store replication is not required

  • Segmented licensing-the ability to license farms separately versus one large pool

Zone Design

A critical component of a MetaFrame XP farm, zones are responsible for collecting data from other servers within the farm and distributing it effectively. Each zone elects a data collector whose role replaces the need for the ICA master browser in earlier versions of MetaFrame. Placement and configuration of zones within a MetaFrame XP farm can greatly affect performance and efficiency of the Citrix farm. As shown in Figure 3-24, zones can be modified via the Citrix Management Console under the Properties dialog box for the Citrix farm.

click to expand
Figure 3-24: Configuring zones with the Citrix Management Console

Citrix recommends that no more than 100 servers operate under a single data collector. Approximately 70 resolutions per second are supported under a single data collector allowing for optimum performance. Several factors play a role in the performance of the data collector, including:

  • Number of users connected

  • Number of simultaneous logons

  • Number of published applications being load-balanced

To properly test a zone design, careful monitoring must occur to determine any bottlenecks caused by an overworked data collector. Although Citrix recommends maintaining as few zones as possible within a farm, multiple zones will be required if a single data collector cannot handle the load. When requiring multiple zones, try separating zones by subnet to help minimize network traffic. In addition, consider dedicating a data collector for the MetaFrame farm if needed to support the environment. It is recommended to maintain a dedicated data collector for each zone that contains 50 or more servers.

Data Store

As the new method by which MetaFrame XP stores information, the data store is another critical component that must be properly planned. Available in several different flavors, the data store allows administrators to customize their environment to meet the business needs. Based upon ODBC-compliant database engines, MetaFrame XP currently supports three database formats and two connection methodologies.

As discussed in Chapter 2, MetaFrame XP supports Microsoft Access, Microsoft SQL, and Oracle as the data store. Determining which application to use for the data store is based upon several criteria. Table 3-2 illustrates the various usage guidelines.

Table 3-2: Data Store Platform Guidelines
 

Small

Medium

Large

Enterprise

Servers

1-50

25-100

50-100

100 +

Users

<100

<3000

<5000

>3000

Applications

<100

<100

<500

<2000

Recommended Data Store

Access, MS SQL, or Oracle

MS SQL or Oracle

MS SQL or Oracle

MS SQL or Oracle

Another factor in the data store is the mode of access. Citrix supports two modes of access: direct mode and indirect mode. Direct mode allows servers to communicate directly with the data store database to maximize performance. This, however, requires more sophisticated database engines, such as MS SQL or Oracle. Indirect mode was designed to work around the limitations of Access as a database application. By utilizing indirect mode, each server must communicate directly with the IMA services on the host server. The single host server is then the only service directly communicating with Access preventing database corruption. It is recommended that you understand how each of these modes of operation functions and when to utilize the proper mode.

Exam Watch 

For scalability purposes, MS SQL or Oracle is always recommended for medium to large farms. Access should only be used in small environments.

In addition to the platform guidelines and modes of operation, there are also some base considerations used for specific scenarios. These items are dependent upon the environment in which they are used. Considerations include:

  • Database replication is not supported with Access

  • IMA start time is directly impacted by database performance

  • Access only supports indirect mode to maintain the integrity of the database

  • Large server farms should only use MS SQL or Oracle to maintain acceptable performance levels

  • Access is best used in centralized farms

  • Use MS SQL or Oracle with farms employing a large number of printer drivers

Now that you are familiar with issues related to designing server farms, here are several scenario questions.

Scenario & Solutions

What is the recommended limit for servers in a single zone?

100

What database platform(s) is recommended as a data store for enterprise environments?

MS SQL or Oracle

What database platform, used for a data store, only supports indirect mode?

Access



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CCA Citrix MetaFrame XP for Windows Administrator Study Guide Exam 70-220
CCA Citrix MetaFrame XP for Windows Administrator Study Guide (Exam 70-220)
ISBN: 0072193190
EAN: 2147483647
Year: 2001
Pages: 169

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