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[Support #RES-637932]: LDM Upgrade of MAX Internet 2



Hi Gini,

> The NWS TOC trying to gauge impact of upgrade of MAX Internet 2  LDM
> Servers.
> We are currently considering upgrade of MAX from ldm 6.1.0 to ldm 6.4.4
> Although the current LDM version is 6.6.4 -- we have experience with
> upgrade to 6.4.4 and
> proved ability to feed to NCEP from TOC LDM Internet 2.
> Not sure of advantages or disadvantage of using more recent
> versions--please advise

The major features that were added in version 6.5 are:

    The LDM configuration-file now supports "include" statements.

    The "pqact" program now identifies the last, successfully-processed
    data-product in a persistent file.  This allows "pqact" processes
    in a subsequent LDM session to start processing where the previous
    ones left-off.

    Under sufficient product-latency or bad-clock conditions, a upstream
    LDM would not send data-products that it should upon reconnection by a 
    downstream LDM.  This has been fixed.

Be advised, however, that LDM versions 6.5.0 through 6.6.4 have an
operating-system dependent bug in "pqact" that can cause the wrong time
to be assigned to a textual data-product with a WMO header (the NEXRAD
Level II products are not in this category) near month transitions.
This will be fixed in version 6.6.5, which I'm about to release.

The major feature that was added to version 6.6 is:

    Downstream LDM processes now identify the last, successfully-received
    data-product in a persistent file.  This allows a downstream LDM process
    in a subsequent LDM session to start where the previous process left off.

More information on these features and on bug fixes can be found in
the file CHANGE_LOG, which is in the top-level source-directory of every
LDM distribution.

> -- but
> but I understand SR is going to LDM 6.4* .  The MAX systems are
> maintained remotely and
> without anyone on site to hit the reset button if needed and therefore
> we would like to choose the
> safest path with minimal disruption.
> 
> We would appreciate Unidata advice on proposed upgrade -- see details
> attached.

Due to the product-time bug in "pqact", I wouldn't upgrade to version
6.5 -- unless you don't do any "pqact" processing of textual WMO
bulletins.

It should be safe to upgrade to version 6.6.5 -- when I release it --
but, I understand that upgrading to it might be a hard sell because
it would be the latest release.

If you decide to upgrade to version 6.4.4, then I recommend upgrading
to version 6.4.6, instead, because of the bug fixes.

> Do those sites receiving the filtered data set  need to upgrade or
> configure ldmd.conf to maintain the filter?

I take it that the new products will be sent from Southern Region
to the Max and should then be relayed to a few, selected downstream
sites -- and only those sites -- and that the feedtype of the new
products is also NEXRAD2.  In that case then, yes, the LDM on the
Max will have to be upgraded to 6.4, at least, in order to enable
"upstream filtering" and prevent the new products from being
relayed to the wrong downstream sites (which, undoubtably,
request them using the feedtype/pattern pair "NEXRAD2/.*".

In order to devise new LDM configuration-file entries that will ensure
proper relaying, I need to know the pattern for the product-identifier
for the new products and how it differs from the current product-
identifier.  Would you please send that to me.  I'm looking for
something in the product-identifier that can be easily matched in
order to differentiate between the two classes of NEXRAD2 products.
This difference is key to upstream filtering as well as proper
processing of the new products via "pqact".

> Can you advise what  might happen if those sites that are planned for
> exclusion from the new data set do receive it?

If the new data-products have a feedtype and a product-identifier
that matches an entry in a "pqact"s configuration-file, then the
"pqact" process will attempt to process the product.  I'm afraid
I don't know how successful that will be because I don't know the
processing details (e.g., can the current NEXRAD2 decoder handle
the new format?).

> Thanks for your help
> Gini Galvin
> System Administrator
> NWS/OCIO/TOC/TSB
> 301 713 0882 x 176
> 240 393 3348 c

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: RES-637932
Department: Support LDM
Priority: Normal
Status: On Hold


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