[IDD #NLC-477499]: Re: [ldm-users] FNMOC-NOGAPS LDM/IDD Feed

Hi Art,

Sorry for the slow response...

re:
> Good news... our department has given approval for Penn State to act as a
> top-tier feed for CONDUIT data!  If that's still the direction Unidata
> wishes to take, I'm ready to move forward with configuration changes.

Excellent!

> I have a question about failover/redundancy...  in my current LDM relay
> LVS cluster I use one of my three relays as the data ingester.  To provide
> for redundancy, however, a second relay is configured to feed from this
> primary ingester as a primary feed, but then also lists all the remote
> feed sources as alternates.  In the case where the main ingestor goes
> down, this secondary ingestor automatically continues ingesting data from
> the remote sites to continue operation.  The third relay feeds from the
> first two relays as primary and alternate.
> 
> This seems like a pretty good arrangement to me but it has a down side...
> the secondary ingester seems to flip-flop between feeding from our local
> primary ingester and the remote feed sites, which adds some level of
> additional load to our networks and the remote feed systems.

Are you concerned about the duplication of traffic when the secondary
ingester is feeding from a remote (i.e., non-PSU) site?  For reference,
the 2 accumulator machines for our IDD relay cluster redundantly request
all feeds possible from two or more upstream sites.  We force those
connections to all be primary by making sure that the requested feed
patterns are treated as being different (i.e., one will use ".*" while
the other will use "(.*)"; these are equivalent by are seen as being
different by the LDM code that sets primary/secondary feed status).
 
> My concern
> is how I would implement such a redundant arrangement if we connect direct
> to NCEP since they only allow four top-tier connections whereas our
> primary/secondary ingesters would both be trying to feed from them at
> various times in the above configuration.  Can you think of a better way
> to do this?

I would have your secondary ingester point at a non-NCEP machine like
idd.cise-nsf.gov.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: NLC-477499
Department: Support IDD
Priority: Normal
Status: Open