Step 2: Planning an ArcGIS Server site configuration
An ArcGIS Server system can consist of one or more computers, depending on the needs of your organization. It's therefore advisable to plan your ArcGIS Server system configuration before installing ArcGIS Server. This section includes an overview and some common system configuration scenarios to help get you started on planning your ArcGIS Server system.
The ArcGIS Server system architecture
An ArcGIS Server system is made up of some of the following components:
- GIS server—The GIS server hosts your GIS resources, such as maps, globes and address locators, and exposes them as services to client applications.
The GIS server is composed of two distinct parts: the server object manager (SOM) and server object containers (SOCs). The SOM manages the services running on the server. When a client application requests the use of a particular service, it's the SOM that actually gives one out for the client to use. There is only one SOM per GIS server.
The SOM connects to one or more SOCs. The SOC machines—also referred to as container machines—contain, or host, the services that the SOM manages. Depending on your configuration, you may run the SOM and SOC on different machines and also have multiple SOC machines. The figure below shows an SOM machine connected to two SOC machines.
- Web server—The Web server hosts Web applications and Web services that use the resources running on the GIS server.
- Clients—Client applications are Web, mobile, and desktop applications that connect over HyperText Transfer Protocol (HTTP) to ArcGIS Server Web services or ArcGIS Server local services over a local area network (LAN) or WAN.
- Data server—The data server contains the GIS resources that have been published as services on the GIS server. These resources can be map documents, address locators, globe documents, geodatabases, and toolboxes.
- Manager and ArcCatalog administrators—ArcGIS Server administrators can use either Manager or ArcCatalog to publish their GIS resources as services.
Manager is a Web application that supports publishing services, administering the GIS server, creating Web applications, and publishing ArcGIS Explorer maps on the server.
ArcCatalog includes a GIS servers node that can be used to add connections to GIS servers for either general server usage or administration of a server's properties and services.
- ArcGIS Desktop content authors—To author the GIS resources, such as maps, geoprocessing tools, and globes, that will be published to your server, you will need to use ArcGIS Desktop applications such as ArcMap, ArcCatalog, and ArcGlobe. Additionally, if you're creating a cached map service, you'll need to use ArcCatalog to create the cache.
There are many possible ArcGIS Server system configurations. It's possible to run all components of ArcGIS Server on a single computer or to distribute the various components across multiple computers. Configurations will vary depending on the needs of an organization, the available computing resources, and the intended use of the ArcGIS Server system. For the SOCs, processing speed and the ability to handle load are important. Some questions to consider are whether the SOCs perform process-intensive functions, whether the nature of those functions and the applications that perform them allow the use of pooled server objects, or whether they require nonpooled server objects. How many server objects will the system need to run at one time, and how many users will the applications that use those server object need to support? Will the Web server computer where any ArcGIS Server Web applications or Web services are running be dedicated to supporting these applications, or will it also be used for other purposes? Answers to these types of questions will assist in planning your ArcGIS Server system.
Configure your ArcGIS Server system based on its intended usage and number of simultaneous users. If you are a developer and intend to use your ArcGIS Server system to build and prototype applications, then you may want to install all the components on a single computer (your development computer). If the anticipated number of simultaneous users of your GIS server is low, satisfying on the order of 100 to 1,000 requests per day, then you may be able to run the entire system on one computer. As you get into higher-volume usage of the GIS server and its associated Web applications, your system should be distributed across multiple computers.
When planning your ArcGIS Server system configuration, there are some common installation recommendations to follow:
- The Web ADF Runtime must be installed on your Web server computer or computers. If you create desktop applications using the Web ADF, the Web ADF Runtime must be installed on any machine on which your application runs.
- The ArcGIS Desktop applications (ArcMap, ArcCatalog, and ArcGlobe) can be used for creating data and as an alternative for managing the GIS server. ArcGIS Desktop can only be installed on a Windows machine. This Windows machine should be able to connect to the GIS server over a LAN.
- Each SOM manages its own collection of SOC machines.
- SOCs can be installed on one machine or many machines. Each machine on which an SOC is installed needs to be added to the list of machines managed by an SOM. Use Manager or ArcCatalog to connect to a machine running the SOM and add the SOC machines that it will manage.
- Each SOC machine requires an ArcGIS authorization file.
- ArcGIS Server Manager (Services Manager) can be used to manage your GIS server. The Services Manager feature includes the ArcGIS Server Manager application and should be installed on the Web server machine. Use the Add ArcGIS Server Instance Tool to add an additional ArcGIS Server instance or modify (remove or update) an existing instance. This tool is installed with the Services Manager, Web Services, and Applications Manager features. To launch the tool, run the <ArcGIS installation location>\ArcGIS\DotNet\AddInstance.exe. For information on the Add ArcGIS Server Instance Tool, see the ArcGIS Server Help.
Common site configuration scenarios
This section presents a series of common configuration scenarios that illustrate how to distribute various installation components across various computer platforms.
ArcGIS Server on a single machine
Multiple Server Object Containers
ArcGIS Server for Microsoft .NET Framework on a single machine
This installation scenario consists of the GIS server (SOM, SOC), and Application Developer Framework on the Web server machine. Additionally, ArcGIS Desktop can also be installed on this machine if another machine is not available to install and run the applications necessary to administer the GIS server.
This type of configuration is useful for those sites with limited computing resources or light server loads or for developers who want to install ArcGIS Server for the purpose of developing applications.
The configuration in the diagram above illustrates the Web server, Application Developer Framework, and GIS Server (SOC and SOM) on one machine. Web Applications can be used to manage your GIS server. ArcGIS Desktop is shown connected to the SOM over a LAN. However, ArcGIS Desktop does not have to be on another machine; it could also be installed on this machine.
Multiple server object containers
Additional SOCs can be added to the ArcGIS Server system configuration as the load on the GIS server increases or to optimize performance. There is no one formula for determining the number of SOCs necessary for a particular system. The number of SOCs will vary depending on the number of server objects, the number of users of those server objects the system needs to support, and the nature of the applications using those server objects—specifically, whether they require pooled or nonpooled server objects.
You can add new SOC machines or additional CPUs to SOC machines already on the system. The SOM assumes that the same licensing exists across all SOCs, meaning if your system makes use of functionality provided by one of the ArcGIS Server options (Spatial, 3D, or StreetMap), then it's assumed that all SOC machines are licensed for that functionality.
The SOM can also be on a dedicated machine. There is no requirement that the SOM and an SOC be installed on the same machine.
The configuration in the diagram above illustrates the Web server, Application Developer Framework, and GIS server (SOC and SOM) on one machine. An additional SOC has been installed on another machine. The load is equally balanced between the two SOCs. Web Applications can be used to manage your GIS server. ArcGIS Desktop is shown connected to the SOM over a LAN. However, ArcGIS Desktop does not have to be on another machine; it could also be installed on one of these machines.
Dedicated Web server machine
Your organization may require your Web server to be on one machine while the ArcGIS Server components reside on a different machine. In this configuration, the Application Developer Framework Runtime must be installed on your Web server machine.
The configuration in the diagram above illustrates the Web server and Application Developer Framework on one machine. The GIS Server (OC and SOM) is on another machine. Web Applications can be used to manage your GIS server. ArcGIS Desktop is shown connected to the SOM over a LAN. However, ArcGIS Desktop does not have to be on another machine; it could also be installed on one of these machines.