Planning and Configuring a Load-Balancing Cluster

Overview of Planning and Configuring a Load-Balancing Cluster

To define a load-balancing cluster (load-balancing logical server), you convert an existing standard logical server. If you have not already defined a standard logical server and a spawner, see Setting Up an IOM Bridge Connection.

Note: If you installed SAS by using the SAS Configuration Wizard, you will already have a logical workspace server named SASMain - Logical Workspace Server, a load-balancing logical stored process server named SASMain - Logical Stored Process Server, or both.

To configure load balancing:

• Plan for the number of servers and server connections in the load-balancing cluster.

  • For SAS Workspace Servers and SAS Stored Process Servers, add multiple servers to a load-balancing logical server.

  • For SAS Stored Process Servers, add multiple connections to each stored process server within a load-balancing logical stored process server.

• Create the standard server metadata. For each server within your load-balancing logical server, plan and set up the standard server, spawner, and login definitions. When you set up your standard server metadata, you must define the servers within the same logical server definition (that will be converted to a load-balancing logical server). You must then define spawners and associate each server with a spawner in order for the server to participate in load balancing. For details about planning for and setting up the standard server metadata, see Standard Server Metadata.

  If you installed and configured with the Advanced or Personal installation option and the SAS Configuration Wizard, then you will already have a logical server named SASMain - Logical Workspace Server or SASMain - Logical Stored Process Server (that contains one or more server definitions).

  Important Note: Each client's credentials must be able to authenticate against any server in the load-balancing logical server (cluster). Therefore, when you define servers within a load-balancing logical server (cluster), you must use the same authentication domain for each server.

  When you set up servers for load-balancing, in the server definition, you can specify either a port or a service for the server.

To set up load balancing, you must plan and set up additional metadata. Here is a summary of the steps:

1. Plan the Logins (For Load Balancing across Multiple Machines). If you have more than one spawner associated with the servers in your load-balancing logical server, you must plan for a login to use for connections between the different spawners.

2. Plan the Load-Balancing Logical Server. You must plan the properties for your load-balancing logical server.

3. Plan the Servers. For each server in the load-balancing cluster, you must plan the appropriate load-balancing properties for the server definition. You might designate certain load-balancing properties on each server definition in order to increase performance for your implementation. For SAS Stored Process Servers, you must also plan MultiBridge connections for each server.

4. Plan the Spawners. You must plan a load-balancing connection for the spawner definition.

5. Set Up Logins (When Load Balancing Across Multiple Machines). You must set up the login definition that you will specify on the load-balancing logical server definition (the logical server credentials) when you convert the logical server to a load-balancing logical server.

6. Set Up Load-Balancing Logical Server. You must convert the standard logical server to a load-balancing logical server definition. When you convert the server to a logical server, you must specify the logical server credentials (used to connect between multiple spawners) and load-balancing properties.

7. Set Up Servers. For each server in the load-balancing logical server, you must set up load-balancing properties on the server definition and, for SAS Stored Process Servers, define MultiBridge connections.

8. Set Up Spawners. You must set up a load-balancing connection for the spawner definition.

Step 1: Plan the Logins (For Load Balancing across Multiple Machines)

To enable load balancing between spawners, follow these steps:

1. Plan the logical server credentials login. This login is used for connections between the spawners in the load-balancing cluster so that the load balancing information can be shared. Each spawner in the cluster must be able to access the login, and the login must be valid on each machine in the cluster.

2. Plan to grant the Administer permission, on the definition for the logical server credentials login, to the user or group that owns the login.

To plan the spawner and load-balancing logical server security, see Planning the Spawner Security. and Planning the Load Balancing Security.

Step 2: Plan a Load-Balancing Logical Server

To plan a load-balancing logical server, determine the following load-balancing properties for the load-balancing logical server definition. These load-balancing properties are specified on the Load Balancing tab of the load-balancing logical server definition's properties in SAS Management Console. For more information about the load balancing algorithm, see Planning the Load-Balancing Algorithm Properties.

• Balancing Algorithm
• Response Refresh Rate (SAS Stored Process Servers and Response Time Algorithm only)
• Cost Per Client (Cost algorithm only)
• Logical Server Credentials

Step 3: Plan the Load-Balancing Servers

To plan load-balancing servers, for each server in the load-balancing logical server, you must determine the following load-balancing properties:

• Maximum Clients (SAS Stored Process Servers only)
• Maximum Cost
• Startup Cost
• Availability Timeout
• Start Size (SAS Stored Process Servers only)
• Recycle Activation Limit (SAS Stored Process Servers only)
• Inactivity Timeout (SAS Stored Process Servers only)

Note: When you set up servers for load-balancing, in the server definition, you can specify either a port or a service for the server.

For SAS Stored Process Servers, you must also plan MultiBridge connections. When you define a MultiBridge connection, you define a unique port for the connection. Each MultiBridge connection represents a server process. For example, if you define a server with three MultiBridge connections, the server can use up to three processes. For an overview of MultiBridge connections, see MultiBridge Connections.

For SAS Workspace Servers, specify the maximum number of clients by using the Maximum Cost and Cost Per Client properties. Use the following formula to determine the values that you need to set:

  x = Maximum Cost / Cost Per Client

In this formula, x is the desired maximum number of clients.

Step 4: Plan the Load-Balancing Spawners

Plan to set up a load-balancing connection for each spawner in the load-balancing cluster. This load-balancing connection is used to communicate between spawners for load balancing. To plan the load-balancing connection, determine the following information:

• name for the connection
• authentication domain (use the same authentication domain that is used for the load-balancing servers)
• host name
• port number (default is 8571)

For detailed information about the fields that are included in the metadata for a spawner, see Fields for Spawner Definitions.

Step 5: Set Up Logins (When Load Balancing Across Multiple Machines)

If you are load-balancing between spawners, then follow these steps:

1. In SAS Management Console, set up the login (logical server credentials) for the load-balancing logical server. To understand user, group, and login definitions, and modify a user and its associated logins, see Defining Users, Groups, and Logins.

2. In SAS Management Console, on the Authorization tab of the load-balancing logical server definition, grant the Administer permission to the user or group metadata identity that owns the login for the logical server credentials.

Step 6: Set Up a Load-Balancing Logical Server

To set up the load-balancing logical server:

1. If you do not already have a standard logical server, see Setting Up an IOM Bridge Connection to create a standard logical server.
   
   
2. In SAS Management Console, select and expand the Server Manager to locate the standard logical server that you want to convert to load balancing.
   
   
3. Select the logical server, and then select Actions Convert to Load Balancing from the menu bar. Confirm that you want to continue.
   
   
4. In the Load Balancing Options dialog box, enter the values that you planned in Step 2:
   
   
   • Balancing Algorithm
   • Response Refresh Rate (SAS Stored Process Servers and Response Time algorithm only)
   • Cost Per Client (Cost algorithm only)
   • Logical Server Credentials

   When you have finished entering the load-balancing parameters, click OK.

   Note: To modify an existing load-balancing logical server, select the logical server and then select File Properties from the menu bar. Select the Load Balancing tab to edit the load balancing options for the logical server.

Step 7: Set Up Load-Balancing Servers

For each server in the load-balancing logical server, you must set up load-balancing properties for the server. To set up load-balancing servers, follow these steps:

1. Use SAS Management Console to specify load-balancing properties:
   
   

   1. In SAS Management Console, expand the Server Manager to locate the server definition.
      
      
   2. Select the server and then select File Properties from the menu bar.
      
      
   3. On the Options tab of the Server Properties dialog box, click Advanced Options.
      
      
   4. On the Load Balancing Properties tab of the Advanced Options dialog box, enter the values that you planned in Step 3:
      
      
      • Maximum Clients (SAS Stored Process Servers only)
      • Maximum Cost
      • Startup Cost
      • Availability Timeout
      • Start Size (SAS Stored Process Servers only)
      • Recycle Activation Limit (SAS Stored Process Servers only)
      • Inactivity Timeout (SAS Stored Process Servers only)

      When you have finished entering the load-balancing parameters, click OK.

2. If you are setting up a SAS Stored Process server, you must set up one or more MultiBridge connections.

   To add a MultiBridge connection:

   1. In SAS Management Console, expand the Server Manager to locate the server definition that you want to add a connection to.
      
      
   2. Select and expand the server definition, and then select Actions Add Connection from the menu bar. The New Connection Wizard appears.
      
      
   3. Select MultiBridge Connection and then click Next.
      
      
   4. Specify a Name and optionally a Description for the new connection, and then click Next.
      
      
   5. Specify the Authentication Domain, Host Name, and Port Number for the new connection.

      When you are finished entering information in the fields, click Next. The parameters for the new connection will be displayed.

   6. Click Finish to define the connection and return to the SAS Management Console main window.

Step 8: Set Up Load-Balancing Spawners

For each spawner in the load-balancing cluster, you must set up a load-balancing connection.

To add a load-balancing connection:

1. In SAS Management Console, expand the Server Manager to locate the spawner definition that you want to add a connection to.

2. Select the spawner definition, and then select Actions Add Connection from the menu bar. The New Connection Wizard appears.

3. Select Load Balancing, and then click Next.

4. Enter a name and description for the connection. Click Next.

5. Specify the Authentication Domain, Host Name, and Port Number for the new connection.

   When you are finished entering information in the fields, click Next. The parameters for the new connection will be displayed.

6. Click Finish to define the connection and return to the SAS Management Console main window.