Re: 19990201: ldmping/failover question

On Mon, 1 Feb 1999, Unidata Support wrote:

> 
> ------- Forwarded Message
> 
> >To: Unidata Support <address@hidden>
> >From: Maureen Ballard <address@hidden>
> >Subject: ldmping/failover question...
> >Organization: UK Ag Weather Center
> >Keywords: 199902011747.KAA06761
> 
> I was trying to understand how the failover command works. I know that
> it will switch betweent he primary and secondary feeds based on the
> output of ldmping. I wanted to know if the ldmping checks to see if the
> upstream is alive, or if it specifically checks for LDM "traffic flow"?

Maureen,

The ldmping command checks that a LDM is running on a host. It really
doesn't check the traffic flow but it does state the time it takes for the
nullproc check to return. 

> It seems to me that on occasion, our upstream has a high latency and it
> would be better if we had switched to our failover site but we haven't.
> 
This is a judgement call on your part, I would install the failover script
and if it doesn't do the job don't use it. SOme sites like it, some don't.
It's not 100% reliable. A future release of the LDM will have automatic
failover.


> I have switched our primary upstream to weather.admin.niu.edu as advised
> from Robb on Friday (with many, many thanks!). Just trying to get a
> better grasp on how these things work!

It takes some time to find the right connections. Once you find one, you
hope some ISP doesn't change the paths. It's an iterative process of trial
and error until one gets a good connection. It's much better now, the
connection paths use to change all the time. 

Robb...


> 
> Thanks!
> 
> Maureen
> --
> ========================================================================
> 
> Maureen Moore Ballard                   address@hidden
> Staff Meteorologist                           ph:  606-257-3000ext244
> Ag. Weather Center                         fax: 606-257-5671
> 243 Ag. Engineering Bldg
> Dept. of Biosystems and Ag. Engr.
> University of Kentucky
> Lexington, KY 40546-0276
> HOMEPAGE   http://wwwagwx.ca.uky.edu
> 
> You don't stop laughing because you grow old;
> you grow old because you stop laughing.
> =========================================================================
> 
> 
> 
> 
> ------- End of Forwarded Message
> 

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================