[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[LDM #QCK-282686]: Implementation of redundant connections



Hi Joe,

re:
> We have a data provider that provides us two separate connections and
> have our ldmd.conf entries as expected:
> 
> Request EXP ".*"   IPAddress1    <primary>
> Request EXP ".*"  IPAddress2      <secondary>

In current versions of the LDM the PRIMARY and SECONDARY pieces of LDM
configuration file REQUEST lines mean nothing as the LDM will autoswitch
between multiple connections that have the exact same extended regular
expression defining the set of products desired.

Assuming that you are running a current (current means non-archaic)
version of the LDM, your REQUEST lines will result in your LDM
putting one of the connections in a primary role and the other
in secondary.  These roles can flip if the number of products
in the secondary feed make it into the receiving LDM queue over
a certain period of time (I think the period is 1 minute, but I
may be wrong).

re:
> Is there a way in the ldmd.conf or pqact that we can only get
> data from the primary IP and only get data from the secondary
> if the primary goes down?

No, but your setup will minimize the network bandwidth used
since the connection in secondary mode will be offered products
one by one and not sent if those products have already been
received and are in the local LDM queue.

One way to fulfill your apparent desire to only get products
from one upstream connection at a time is to create two
LDM configuration files and then run a process out of cron
that monitors the existing connection for viability (i.e.,
receiving products).  The logic would be if the "current"
connection is not receiving products, swap the second LDM
configuration file to be active and then restart the LDM.

Comment:

We feel that the setup where the LDM will promote one feed
to primary mode and demote the other to secondary mode
is much more reliable/easier to use than the use of two
LDM configuration files.

re:
> Thank you,

No worries.

Cheers,

Tom
--
****************************************************************************
Unidata User Support                                    UCAR Unidata Program
(303) 497-8642                                                 P.O. Box 3000
address@hidden                                   Boulder, CO 80307
----------------------------------------------------------------------------
Unidata HomePage                       http://www.unidata.ucar.edu
****************************************************************************


Ticket Details
===================
Ticket ID: QCK-282686
Department: Support LDM
Priority: Normal
Status: Closed
===================
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata 
inquiry tracking system and then made publicly available through the web.  If 
you do not want to have your interactions made available in this way, you must 
let us know in each email you send to us.



NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.