so here's a wierd one

Steve Emmerson steve at unidata.ucar.edu
Tue Apr 3 09:04:11 MDT 2007


Daryl,

> The issue that I have with the newer LDM 6.6 is that I have 5 machines 
> producing products in the EXP feedtype.  I have two data collector 
> machines that request EXP .* from these 5 machines.  This seems to 
> horribly confuse LDM.  My only recourse is to make sure the data 
> collectors are using slightly different feed requests so that it 
> continues to get products from all 5 upstream hosts.

If the 5 upstream hosts are producing different products (i.e., every 
product is created on one and only one host), then the feeds are 
disjoint even though naive REQUEST entries would be identical.  In this 
situation, I would expect the LDM to become confused.  The solution --- 
as you've discovered --- is to have each pattern in the REQUEST entries 
be a unique string.  This is most easily done by using parentheses.  For 
example,

     REQUEST EXP .* host1
     REQUEST EXP (.*) host2
     REQUEST EXP ((.*)) host3

Assuming no other REQUEST entries for the same data, then the above will 
result in permanent PRIMARY mode connections to the three hosts.

> I'm probably not using LDM as it was designed for :)  My local topology 
> looks more like spaghetti than a tree.

Actually, spaghetti (or a web) is good.  We recommend duplication of 
(identical) REQUEST entries to provide robustness when the data-feeds 
are, in fact, identical.  Your non-identical feed situation is unusual, 
but should be accommodated by the above mechanism.




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