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

[LDM #NTV-128842]: LDM feeds and Virtual Interfaces

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [LDM #NTV-128842]: LDM feeds and Virtual Interfaces
  • Date: Mon, 24 Apr 2006 15:17:54 -0600
Mark,

> I want to be able to pull data from the regions using virtual
> interfaces, I am fairly certain this is possible, but is there anything
> special I need to know about setting up LDM for this?  In other words, I
> have LDM feeds setup for each of the regions with IPs we don't currently
> use.  However, I need to upgrade my LDM server OS's and want to be able
> to switch the region feeds to other servers using the existing feed
> allows and virtual interfaces.  Anything I should know?

I think I understand what you're asking but I'm not sure.  Let me restate
your situation.  Let me know if it's incorrect.

Your LDM configuration-file has REQUEST entries for data from each of
the four NWS regional headquarters.  You want to be able to take your
LDM host offline and have another LDM on another host request and 
receive the data.  You want the second host to have the same IP address
as the original host.

I'm not sure why the last point is necessary because the easiest way to 
accomplish this is to have the ALLOW entries in the LDM configuration-
files of the regional HQ-s allow for any host in your domain, e.g.,

ALLOW ANY ^128\.127\.140\.[0-9]*$

Given that you can setup your LDM hosts to use the same IP address, 
however, it should be possible to accomplish what you want if the LDM-s
on the hosts all have access to the same product-queue file.  This is
necessary in order for the LDM to request data-products from the last
successfully-received data-product.  Because of the high throughput of
the LDM system and because the product-queue is usually memory-
mapped, the product-queue is almost exclusively found on a local disk.
Consequently, it would seem that you would need to have a multi-homed
disk in order to do what you want.

> Interdum feror cupidine partium magnarum Europae vincendarum
> 
> Mark Haney
> Sr. Systems Administrator
> ERC Broadband
> (828) 350-2415

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: NTV-128842
Department: Support LDM
Priority: Normal
Status: Closed