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[LDM #PXP-182972]: LDM-- add second IP address as backup

Hi Wen,

> NCEP/NCO has been running LDM version 6.7.0 on IBM Unix machine.
> We are asking the possible solution for adding second IP address as backup
> data feed so the second data feed is only activated when the primary
> feed is down.

There is nothing in the LDM that allows this directly.  The best way to 
your goal is to:

- create 2 ldmd.conf files: one with the REQUEST(s) to the first IP and the 
  with the REQUEST(s) to the second IP

- create a script that is run through cron once per minute that checks to see
  if the LDM running at the first IP is up

  If it is not, the script should shutdown the ldm; swap ldmd.conf files and
  then restart.


- in order to provide continuous ingest, most sites implement redundant
  feed REQUEST(s) in the ldmd.conf file.  The connection that is getting the
  data the fastest will operate in PRIMARY mode (all data will be sent to
  it without asking if it wants each product individually) and the other
  will operate in SECONDARY mode (the upstream LDM will ask the downstream
  if it wants each product individually).  If either of the connections
  fail, the other connection will be promoted to run in PRIMARY mode if
  it is not already running in PRIMARY mode.  This setup is attractive
  since it insures delivery of products in as short a time as possible
  while minimizing bandwidth (in SECONDARY mode, the product is not sent
  before the downstream acknowledges that it wants it).

  Can you not use a setup like this?

> Thanks,
> Wen


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Ticket Details
Ticket ID: PXP-182972
Department: Support LDM
Priority: Normal
Status: Closed

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