3. LDM Site Managers

1. Obtain upstream data feed source

The first thing you need to do is to find out who your upstream feed site(s) will be. Because Jackson State University is already a licensed participant of Unidata, we just contact the UPC at support@unidata.ucar.edu. They currently assign sirocco.srcc.lsu.edu (IP: 130.39.188.220) as our upstream feed site.

2. Configuring ldmadmin

ldmadmin is a Perl script which forms a high-level, command-line interface to the LDM system. We can configure the file follow the instructions in the file's comment lines. The following is an example to change the size of the product queue.
$pq_size = 200000000 (size of the product queue, default is 100000000 bites)

3. Configure LDM Configuration File (ldmd.conf)

This configuration file is read by the LDM server, rpc.ldmd, on start-up and it has multiple functions. It controls from which computers the server will accept data and to which computers it will send data. It determines what data this server will request from others. It also determines what other programs will be run in the same process group with the server. When you wish to change any of these things, this file will need to be edited. The changes will not take effect until you restart the server.

By default, ldmd.conf is found in the etc subdirectory of the LDM installation. The following is what we change the ldmd.conf file:

• Add "request" lines for your upstream feed site(s):

request DDS ".*" sirocco.srcc.lsu.edu
request IDS ".*" sirocco.srcc.lsu.edu

DDS: Domestic Data Service
IDS: International Data Service
We just receive these data now, but will receive more data in the future.

• In the upstream ldmd.conf ask to have "allow" lines for your feed site:

allow DDS sirocco.srcc.lsu.edu
allow IDS sirocco.srcc.lsu.edu

• Uncomment the exec lines for pqact and (if necessary) pqsurf

The program pqact is to process products in a Unidata LDM product queue. The program is to split surface bulletins and process the observations.

• Check that the upstream configuration is in place, run:

% notifyme -vl - -h "upstream site"
This result should be a list of products the upstream site is receiving

4. Configure the pqact.conf file

This configuration file associates data-product identifiers (such as WMO headers) with commands that specify what to do with those data products. It is an editable text file that is read by the pqact utility when it first starts up, and again when directed to reread it. All Unidata sites should customize this file to establish:

• Which data products they wish to store and/or decode;
• Where the data products are to be written or what decoders are to be invoked on the data products;
• What other actions are taken when specific data products arrive.

  A sample configuration file is provided in src/pqact/pqact.conf in the source distribution or in etc/pqact.conf in the binary distribution. This file contains many commented sample entries for various sets of products. It can serve as a starting point for a configuration file adapted to your site. We will configure it for GEMPAK later.

  5.Configure the scour Configuration File (scour.conf)

  This configuration file tells the scour utility when locally-created data files should be removed to make room for more. This file is found in the etc subdirectory of the LDM installation. This configuration file is documented internally. To configure the file, open it in a text editor and follow the instructions in the file's comment lines.