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Conference iosg::all-in-1

Title:ALL-IN-1 (tm) Support Conference
Notice:Please spell ALL-IN-1 correctly - all CAPITALS!
Moderator:IOSG::PYECE
Created:Fri Jul 01 1994
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2716
Total number of notes:12169

2660.0. "ALL-IN-1 and MTA sets (MTA_NODE)" by ATZIS1::EHRLICH_K (Never met a Lady like her before!) Mon May 05 1997 14:00

    Hi,
    
    	we have to do some changes in CoV's MAILbus-backbone.
    (Yeah, it'S too stable ;-) We'd like to build a MTA-set
    with at least 2 MTAs.
    
    From the MAILbus docs this seems pretty easy to do, but one
    particular question is still open for me:
    
    What'S with the UA, esp. ALL-IN-1 as the UA.
    
    � Must we apply all NSAP addresses in the MTA_NODE logical
      or is it enough only specifying one of the members of the MTA-set.
      But how will the UA then be able to contact the other one, if this
      MTA fails.
    
    � Sender/Fetcher: I think it'S a good idea to have One Sender/Fetcher
      pair connected to each member of the MTA-set. Therefore defining
      the MTA_NODE processlogicalnametable ...
    
    Any inputs are welcome!
    
    Many thanks for your kind support,
    Cheers
    Charly
    PS: Yes, I read #2090.
T.RTitleUserPersonal
Name		DateLines
2660.1lets work together...OSITEL::rtont2.rto.dec.com::rtoms1::schaefereSI-OfficeTue May 06 1997 12:0912
 Hi Charly,

 I have no answer yet but similar questions. My customer wants to operate
 two MTAs (no MTA set) in a Alpha VMS Cluster (2 nodes) with transport
 TCP/IP.
 I know that the DSA can only be active on one node at a time but that the 
 MTA can run on both nodes in the cluster simultaneously. 
 
 The details, how to set up the DSA and MTA und the UA (ALL-IN-1 V 3.2)
 I do not know at the moment.,

 regards, Erich
2660.2No experiences with MTA sets (.0)???ATZIS3::EHRLICH_KNever met a Lady like her before!Wed May 07 1997 11:2228
    Hi,
    
    	after looking/trying/playing around yesterday in office, I found
    that 
    
    � MTA sets are only good for the MTA itselve (performance,realability)
      because they can split the mail-load via 'round-robin'.
      And this is a great benefit if acting as a area-'router' or a 
      boundary server.
    
    � in the MAILbus 400 architecture slides: The UA has to be sure that
      'he' can contact all members of the MTA sets. 
     
    -> So, from the UA-point-of-view: This is really no benefit.
       YOU have to make sure, HOW to split your UAs to the members of the
       MTA set. So, you can ALL-IN-1 UA connect to member1, XMR UA to
       member2, maybe another ALL-IN-1 UA to member3 but, that'S all.
       No way to have it automatic.
       Guess, what happens if one member fails....No failover...
    
    Or did I miss something? 
    
    Cheers
    Charly
2660.3IOSG::MARSHALLMon May 12 1997 13:5626
A few comments:

re .1: the MTA can run on both nodes in the cluster simultaneously

This is not really a supported configuration.  You are only supposed to run one
MTA on one node in a cluster.  You can make it work on more than one node, but
it's not recommended.

re .2: yes, you are correct.  The MTA's client interface (XAPI) available to
user agents does not provide an automatic mechanism for connecting to multiple
MTAs (in an MTA set or otherwise).  In the simple case, all clients on one node
connect to one MTA (on the same or a different node) as defined by the MTA_NODE
logical.  You could modify this so that different clients 'see' different values
of the logical and hence use different MTAs, but as you observe, this is a
manual operation.

You are also correct to observe there is no automatic failover between MTAs in
an MTA set.  You can set-up a standby MTA so there is minimal manual
intervention (and hence time) required to bring up a standby MTA in the event
that the primary MTA, or its host node, fails, but that's about it.

If you want more automation of load sharing and failover/recovery, it's probably
best if you submit a formal product requirement to the Product Manager, Geoff
Oades.

Scott
2660.4Thank YOU, Scott!ATZIS2::EHRLICH_KNever met a Lady like her before!Mon May 12 1997 15:361