Server Objects, Application Servers, and Logical Servers

About Server Objects and Server Groupings

In the SAS Metadata Repository, each server process that executes SAS code is represented by a server object. In the metadata, the attributes for each server object contain information such as the following:

the name of the machine that is hosting the server
the TCP/IP port or ports on which the server listens for requests
the SAS command that is used to start the server

The intermediate level of organization is called a logical server object. SAS servers of a particular type, running either on the same machine or on different machines, can be grouped into a logical server of the corresponding type. For example:

A logical workspace server is a group of one or more workspace servers.
A logical pooled workspace server is a group of one or more workspace servers that are configured to use server-side pooling.
A logical stored process server is a group of one or more stored process servers.

The logical servers are then grouped into a SAS Application Server. The following figure shows a sample configuration:

SAS Application Server Components: Sample Configuration

Diagram of an application server that contains multiple logical servers, each of which contains multiple server components

Application servers and logical servers are logical constructs that exist only in metadata. In contrast, the server objects within a logical server correspond to actual server processes that execute SAS code.

Purpose of the Application Server Grouping

Application servers, which are groupings of logical servers, provide the following functionality in the SAS Intelligence Platform:

SAS applications can request the services of a group of logical servers by specifying a single application server name.

For example, a user can set up SAS Data Integration Studio to send all jobs to a specific SAS Application Server. Each time the user runs a SAS Data Integration Studio job, the SAS code that is generated is executed by a workspace server that is contained in the specified application server.
System resources, such as SAS libraries or data schemas, can be assigned to a specific application server. This assignment ensures that all of the logical servers contained in the application server will be able to access these resources as needed, subject to security restrictions.

For example, if a SAS library is assigned to a specific application server, then any application that runs jobs on that server will automatically have access to the library, subject to security restrictions.

Purpose of the Logical Server Grouping

Logical servers, which are groupings of individual servers of a specific type, provide the following functionality in the SAS Intelligence Platform:

Users or groups of users can be granted rights to a logical server, thereby providing access to each physical server that the logical server contains. You can also use permissions to direct specific users or groups of users to specific physical servers within a logical server grouping.
If one physical server in a logical server grouping fails, the other servers are still available to provide continuous processing.
Load balancing can be implemented among the servers in a logical workspace server, logical stored process server, or logical OLAP server. Load balancing is configured by default for the SAS Pooled Workspace Server and SAS Stored Process Servers.
Workspace pooling can be implemented among the servers in a logical workspace server.

For more information about SAS Application Servers, see the SAS Intelligence Platform: Application Server Administration Guide.