How to distribute pooled 3270 application resources and LUA application resources across multiple computers that are running SNA Server or Host Integration Server (893267)

Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

INTRODUCTION

In an environment where 3270 applications or Logical Unit Application (LUA) applications receive resources from two or more servers in a pooled Microsoft SNA Server-based subdomain, the resources on one server may be exhausted before the resources on other servers are used.

Example

Note This example discusses LUA logical units (LUs). However, it may also apply to 3270 LUs.

Scenario

ServerA has multiple connections with multiple LUA LUs.
ServerB also has multiple connections with multiple LUA LUs.
All LUA LUs from both servers are part of a pool that is named LUAPool.

Behavior

When a client requests an LUA session by specifying the LUAPool pool, the session may be granted from either ServerA or ServerB. If ServerA provides the LUA session, any later resource request from the same client will be made to ServerA first. This behavior occurs even though LUA resources are available on ServerB.

MORE INFORMATION

By default, when the client side SNADMOD is locating a resource, it will first try the server that it already has a connection to. The client side SNADMOD does this before it tries other servers.

Note SNADMOD is a communications module.

To distribute pooled 3270 application resources and LUA application resources, you can add the ResLocFlags DWORD value to the registry on every client computer that is running the LUA application or the 3270 application. You must set the ResLocFlags DWORD value to 1. When you do this, the client side SNADMOD will not first try the server that it already has a connection to. Instead, the client side SNADMOD will equally consider all the servers.

Note By default, if the value of the ResLocFlags DWORD value is not set, the value is zero.

To add and to set the ResLocFlags DWORD value, follow these steps:

Click Start, click Run, type regedit, and then click OK.
Locate and then click the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SnaBase\Parameters\Client
On the Edit menu, point to New, and then click DWORD Value.
Type ResLocFlags, and then press ENTER.
On the Edit menu, click Modify. In the Value data box, type 1, and then click OK.

REFERENCES

For additional information about the ResLocFlags DWORD value and LU6.2 applications, click the following article number to view the article in the Microsoft Knowledge Base:

266275 HIS 2000 Client LU6.2 load balancing across SNA Server services

For additional information about the ResLocFlags DWORD value and TN3270 servers, click the following article number to view the article in the Microsoft Knowledge Base:

185446 TN3270 server LUA pool use should load balance across servers

For additional information about load balancing on SNA Server (all versions) and on Microsoft Host Integration Server 2000 and later versions when the ResLocFlags DWORD value is not used, click the following article number to view the article in the Microsoft Knowledge Base:

128244 SNA Server load balancing and hot backup