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20030703: Twio quick questions!

>From:  Gilbert Sebenste <address@hidden>
>Organization:  NIU
>Keywords:  200307040208.h6428HLd002178 LDM-6 IDD ldmd.conf request

Hi Gilbert,

>Before I head out and away for a few days...
>
>1. If I request IDS|HDS|DDPLUS etc on one line in my ldmd.conf, the data 
>will now come through just as fast as if I had broken up the feeds to use 
>the machine's IP or alternate addresses to get the data, right?

Correct.  LDM-6 does not accumulate feed requests to upstream hosts
into single rpc.ldmds like LDM-5 did.  This makes the job of splitting
feed requests as simple as making multiple lines in one's ldmd.conf
file.  It also, however, places the onus on the requesting user to try
and put as many feeds in a single request line as makes sense.  For
instance, the following two request lines in most circumstances would
be better made as one:

request UNIWISC ".*"    upstream.feed.host
request FSL2    ".*"    upstream.feed.host

is better done as:

request UNIWISC|FSL2    ".*"    upstream.feed.host

The reason is that there will be one rpc.ldmd running on your client
AND only one rpc.ldmd running on the server.

Another comment about setting up entries in ldmd.conf for LDM-6.  We
would greatly appreciate folks making all data requests by fully
qualified host names and not name aliases or IP addresses.  The reason
is that the real time statistics tracking of topology trees is
simplified when everyone uses fully qualified host names AND, most
importantly, reports back their real time statistics through
the exec line in ldmd.conf:

exec    "rtstats -h rtstats.unidata.ucar.edu"

>2. Now that most folks are on 6.0.13, how does the topology data losses 
>look after the switchover? Better and by how much?

The improvement in data delivery when both the client and server LDM
are both version 6 is dramatic.  Quantifying how much better this is
can not be done accurately for the entire IDD due to various
complexities.  Several individual examples have shown that latencies
for feeds like IDS|DDPLUS or HDS have gone from a couple of thousand
seconds to near zero after the upgrade to LDM-6.

Sites still running LDM-5 should upgrade to the latest LDM-6 release as
soon as they are able.  To ease the transition and assist in tuning, we
are willing to do the installation and reconfiguration for any site
that provides us with the appropriate logons.  Interested parties
should contact Unidata User Support <address@hidden> for more
information.

>Personally, I am very impressed with LDM 6.0.13. Rock stable with RedHat 
>Linux 9.0, all patches applied.

Thanks for the kudos.  All of the UPC folks involved with LDM
development and support really do appreciate positive feedback from
time to time.

Cheers,

Tom
--
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* Tom Yoksas                                             UCAR Unidata Program *
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