Be the Plumber: Resolving Host Monitor Issues

The Problem

Your host monitor stopped working.  You’ve turned it off and on and the propagation tab only shows a “trying to connect” message.  Now what?

First of all, the Host Monitor is a bi-directional connection between Visual LANSA and LANSA on the iSeries.  I like to think of the host monitor as a communications pipe with a fitting on each end.  One fitting connects the pipe to your PC while the other connects it to the iSeries.

When you ask Visual LANSA to end the host monitor, it attempts to disconnect the pipe on both ends.  A failure here is almost always on the iSeries side.  When you turn on your host monitor, a new pipe is connected to the existing fittings.  If there is already a pipe connected to either end, starting the host monitor will fail.

Resolution Part 1 – End It For Real

Sometimes when you close Visual LANSA or turn off the host monitor, the pipe is not fully disconnected on the iSeries side.  To determine if this is your issue, log into the iSeries as yourself and execute the command below.  If you see one or more active jobs that start with MON_, the host monitor did not end even though you asked it to.  End them with option(*immed).

[code]WRKUSRJOB * *ACTIVE[/code]

Resolution Part 2 – Clearing the iSeries Clog

The host monitor holds data about the state of your connection in two iSeries libraries. When there are issues ending the host monitor, the pipe usually gets clogged here.  Setting aside the analogy for a moment, the problem is usually with a data area called XQUEUE.  An object lock that won’t release will be attached to it.

The two host monitor libraries need to be cleared so that the host monitor brain can be reset.  To figure out the library names, truncate your user profile at six characters.  (TJENSEN becomes TJENSE).  Perform the following commands using this truncated text to locate the correct libraries.  If you have multiple copies of Visual LANSA, you will have multiple versions of each of these libraries.  If so, make sure all copies of VL are closed (best option) or that all host monitors are ended (second-best option) and clear ’em all!



You are about to clear these libraries. Prior to this, make sure you’ve ended all active host monitor jobs that are yours (from issue #1 above).  The clear commands will look similar to mine below.  Please note: if one of the clear commands fail the first time, Congratulations!, you found the problem. Perform the clear again and it should succeed the second time.


And The Winner Is…

Launch Visual LANSA and try to start the host monitor.  It should start without issue.

If the host monitor fails to start, the pipe fitting on the Windows side may have crashed hard when it was ended. I’ll bet you can guess this one.  It is the typical Windows answer of reboot your PC and try it again.


Posted on March 9, 2011, in Lansa. Bookmark the permalink. Comments Off on Be the Plumber: Resolving Host Monitor Issues.

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