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[LDM #HAI-188407]: dockerized LDM - multiple instances

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  • Subject: [LDM #HAI-188407]: dockerized LDM - multiple instances
  • Date: Tue, 19 Jun 2018 14:49:19 -0600
Hi Erik,

re:
> I think my overall need for redundancy arises from server reboots that
> occasionally come from software updates.  How would you handle situations
> such as needing to reboot a LDM server without causing a disruption of
> downloaded data?

The reason that the LDM uses a queue is to provide elasticity in data
movement.  When a downstream (receiving) LDM goes down for any reason
(e.g., software updates, power outage, etc.) and then comes back up, it
will REQUEST data from its upstream(s) starting from the last product
received in each datastream for which it has a standing REQUEST.  If the
LDM queue(s) on the upstream(s) machines is(are) sufficiently large and the
network connection between the downstream and upstream is sufficiently
robust (i.e., fast), no data will be lost.  If, however, the downstream
machine goes down for a period of time that is longer than the residency
time of data in the upstream LDM queue(s), then data will be lost.  The
key question then becomes one of how long of a buffer the upstream
LDM queue(s) is(are) providing.

We attempt to provide at least one hour of data for all datastreams in the
IDD.  This means that a downstream machine can go down for a reasonably large
fraction of an hour (the fraction will depend on the network speed and the
volume of data REQUESTed) and still get all of the data REQUESTed as long as
the network connection can handle the data volume.

I hope that this made sense!

Cheers,

Tom
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Ticket Details
===================
Ticket ID: HAI-188407
Department: Support LDM
Priority: Normal
Status: Closed
===================
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