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Re: 20000822: Backup LDM server

Unidata Support wrote:
> 
> ------- Forwarded Message
> 
> >From: Angel Li <address@hidden>
> >Subject: Backup LDM server
> >Organization: University of Miami
> >Keywords: 200008222027.e7MKReN18204 LDM IDD backup feed failover
> 
> Hi,
> 
> I was wondering what the procedure is for making sure I have
> a backup LDM feed. Also, how is failover handled?
> 
> Thanks,
> 
> Angel
> 
> ------- End of Forwarded Message

Hi Angel,

Jeff, the person who handles setting up connections between sites, is out of 
town.  He will set up a backup feed for you when he returns, on Friday or 
Monday.

In the meantime, I will describe to you how failover works.

'failover' is a script to be run from cron.  We advise that you set it up to 
run every 20 minutes.  It's really pretty simple - the script tests whether 
your primary feed is alive.  If not, it tests your failover feed and will 
switch you over if possible.  If you are already feeding from your failover 
site, it will test the primary and switch you back when it can.  For more 
detailed information look at the comments at the top of the 'failover' script.

Here's what the LDM site manager's guide says about how to set up the failover:

 If you are using the new ldmfail script for automated failover on the IDD, you 
must make
 two copies of the ldmd.conf file. The only differences in the two files will 
be the request line
 for your upstream feed, and the names of the files. One file should be named 
ldmd. primary ,
 where primary is the fully qualified hostname of your primary upstream feed 
host (e.g.,
 ldmd.primary.foo.edu ). The request line in this file should ask for data from 
that host. The
 second file should be named ldmd. failover , where failover is the fully 
qualified hostname
 of your failover upstream feed host (e.g., ldmd.failover.bar.edu ). The 
request line in this file
 should ask for data from the failover host.

To see another more succint version of the same instructions (from the LDM 
workshop) take a look at the section called "Configuring lmdfail" at 
http://www.unidata.ucar.edu/packages/ldm/ws/idd_config.html#s0

Please let me know if you have any further questions.

Anne


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Anne Wilson                     UCAR Unidata Program            
address@hidden                 P.O. Box 3000
                                  Boulder, CO  80307
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