MQ was mentioned in a previous reply.  We have it (quite old, but 
sufficient) working for a pretty-much obsolete application on z/VM 5.1.
Check out: http://www.vm.ibm.com/mqseries/

Mike Walter 
Hewitt Associates 
Any opinions expressed herein are mine alone and do not necessarily 
represent the opinions or policies of Hewitt Associates.




"David Boyes" <[EMAIL PROTECTED]> 

Sent by: "The IBM z/VM Operating System" <[email protected]>
08/26/2008 08:22 AM
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"The IBM z/VM Operating System" <[email protected]>



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Subject
Re: IUCV -  What's wrong with this picture?






> 1. Does IUCV infrastructure overhead specifically associated with
number
> of
> connections become prohibitive at some well known point?

There is a limit to the maximum number of connections (a parm on the
IUCV statement in the directory entry; I think the max value for that
parm is 64K, but check your docs -- I don't have manuals with me at the
moment). 
 
> 2. Has anyone had experience with an application having a high IUCV
> connection count like this? If so, what was that experience?

Probably the best example I know of for an application that uses a lot
of IUCV connections is the VM TCPIP stack (yes, I know there is a lot of
VMCF too, but it also uses IUCV.). It seems to be fairly stable and
scales well. 

At a past employer, we had a few applications that regularly had several
thousand IUCV connections open and active simultaneously with no
connection state related problems. The key problem with performance
tuning for those applications was supplying sufficient virtual storage
to provide suitable buffers for the connections, and the need to
dispatch each endpoint every time you needed to send and respond to a
message. Those two things were a lot bigger hit than the IUCV connection
and session management processing. 

Something also to think about is the additional hit of dispatching and
routing messages between VM images if you are planning on permitting
distributed IUCV (a good idea). That's going to mean some additional
work needed from CP to do ISFC, or asking CP to dispatch TSAF or AVS or
IPGATE to get the message frame over to the other system. That can be
significant.






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