SNA Manager Not Setting LUA Pool Size to Actual Number of LUs (173172)

SYMPTOMS

If the configured LUA pool size is larger than the actual number of LUA LUs in the LUA pool, the following symptoms can occur:

If the Close Listen Socket option is selected, the TN3270 server does not close the listening socket after all LUA LUs have been opened. This causes new TN3270 client connection attempts to stops responding when all LUs are in use.

The following Windows NT application event log entries will be logged if the TN3270 server attempts to open an LUA Pool when all LUA LUs in the pool have already been opened:

      Event ID: 1955
      Source:   SNA RUI Application
      Description:
      RUI_INIT failed for LU TN3270, primary_rc=1400, secondary_rc=87000000

      Event ID: 305
      Source:   TN3270 Server
      Description:
      RUI_INIT specifying LU <luname> failed with LUA_UNSUCCESSFUL,
      LUA_COMMAND_COUNT_ERROR

CAUSE

When you assign an LUA Pool to the TN3270 Server in SNA Manager, the LUA Pool TN3270 folder shows the pool size as 30,000, instead of the actual number of LUA LUs in the pool. The LUA pool size can be changed manually.

This problem does not occur using SNA Server 2.11, because the TN3270 Administrator program always sets the correct LUA pool size in the TN3270 configuration file.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 3.0 and 3.0 Service Pack 1 (SP1). This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

With this update applied, when an LUA pool is assigned to a TN3270 service, the session count for the pool is set to the number of LUs in the Pool.

If an LUA LU is added to a pool which is already assigned to TN3270, and the session count is equal to the number of LUs in the pool, then the session count is incremented so that it still equals the number of LUs.

If an LUA LU is removed from a pool which is already assigned to TN3270, and the session count becomes less than the number of LUs in the pool, then the session count is lowered to equal the number of LUs.

If a user manually sets the session count to some number less than the number of LUs in the pool, then the count is not automatically changed when LUs are added or removed from the pool. However if enough LUs are removed so that the session count becomes equal or greater than the number of LUs in the pool, then the session count will start to track any further additions or removals.

For additional information on a separate problem using the TN3270 Server, please see the following article in the Microsoft Knowledge Base:

166846 Cannot Reconnect to TN3270 Server with Close Listen Sockets