Using SAS Grid Manager for Server Load Balancing

SAS servers, such as SAS workspace servers and SAS OLAP servers, are capable of performing load balancing across multiple machines. These servers can be configured to use one of the default algorithms to provide load balancing. However, with SAS Grid Manager installed, you can configure workspace servers and other SAS servers to use SAS Grid Manager to provide load balancing. Because SAS Grid Manager accounts for all of the resource consumption on the machine, it is able to make better decisions about which machine is the best candidate for a server session.

When an application or process (for example, SAS Enterprise Guide) requests a SAS server from the object spawner, the spawner determines which hosts can run the new servers. The spawner sends the list of hosts to SAS Grid Manager, which then determines which host is open and is the least busy. The object spawner then directs the client connection to a server on the least busy node on the grid. If there are multiple servers already running on the machine, then the spawner directs the client to the server with the fewest number of connections. Because the SAS object spawner is not used to start SAS OLAP servers, the request is not processed through the object spawner if the client requests a SAS OLAP server. However, the same load-sharing logic is used to determine which OLAP server is used for the client connection. As a result, the SAS client connections are spread around to all of the servers in the grid.

When using the grid load balancing algorithm, jobs are not started by LSF. As a result, jobs that run on the load balanced servers do not appear as LSF jobs.

For more information, see Understanding Server Load Balancing in SAS Intelligence Platform: Application Server Administration Guide.

SAS Grid Manager can provide load balancing capabilities for these types of servers:

workspace servers
pooled workspace servers
stored process servers
OLAP servers

This configuration provides server-side load balancing for any SAS product or solution that uses one of these servers for processing. Products that can use this configuration include SAS Enterprise Guide, SAS Data Integration Studio, SAS Enterprise Miner, and SAS Marketing Automation.

In order to achieve the benefit of using grid load balancing, you must convert multiple instances of the server type. If you convert only a single workspace server, SAS Grid Manager sends all jobs to that server regardless of the load. If you convert multiple servers, SAS Grid Manager sends the job to the server that is the least busy.

To use the SAS Grid Manager for load balancing for a workspace server or an OLAP server, follow these steps:

In the Server Manager plug-in in SAS Management Console, select the server that will use load balancing.
Select Convert ToLoad Balancing from the Actions menu or the context menu. The Load Balancing Options dialog box appears.

Server Load Balancing Options Dialog Box
Specify the following values:

Balancing algorithm

Select Grid.

Grid server

Select a grid server that was defined during installation and configuration.

Grid server credentials

Select the credentials that the object spawner uses to authenticate to the grid server.
Click OK to save your changes to the server metadata.

To use the SAS Grid Manager for load balancing for a stored process server or a pooled workspace server, follow these steps:

In the Server Manager plug-in in SAS Management Console, select a server that will use load balancing.
Select Properties from the Actions menu or the context menu. The Properties dialog box appears.
Select the Options tab.

Load Balancing Options for a Server
Specify the following values:

Balancing algorithm

Select Grid.

Grid server

Select a grid server that was defined during installation and configuration.

Grid server credentials

Select the credentials that the object spawner uses to authenticate to the grid server.

In addition to modifying these server definitions, you must also change server configuration files. For information about the changes that you need to make, see Understanding Server Load Balancing in SAS Intelligence Platform: Application Server Administration Guide.