Re: [ldm-users] NEXRAD2 Latency/Fragmented Data?

On Mon, 30 Jul 2012, we looked up in the sky. Did we see a bird? A plane?
Nah, it's Super Daryl Herzmann, who wrote:


Steve Emmerson kindly informed me that this is not quite the proper thing to do. Each pqact process should have an unique filename associated with it for when it writes state information to disk. The files can be simple sym links and it will 'trick' LDM just fine. So the recommendation is to simply:

cd /home/ldm/etc
ln -s pqact.gempak_craft pqact.gempak_craft.1
ln -s pqact.gempak_craft pqact.gempak_craft.2
ln -s pqact.gempak_craft pqact.gempak_craft.3

Then in ldmd.conf

exec "/home/ldm/bin/pqact -f NEXRAD2 -p BZIP2/P[A-Z] /home/ldm/etc/pqact.gempak_craft.1"

Hmmm. I thought the issue was rpc not being able to keep up with such a high data feed rate, not I/O.

Also note with the above, that you would be missing the radars starting with D,N, and R :) Here's what I use:

exec    "pqact -p BZIP2/K[A-D] -f CRAFT /home/ldm/etc/pqact.CRAFT"
exec    "pqact -p BZIP2/K[E-H] -f CRAFT /home/ldm/etc/pqact.CRAFT2"
exec    "pqact -p BZIP2/K[I-K] -f CRAFT /home/ldm/etc/pqact.CRAFT3"
exec    "pqact -p BZIP2/K[L-O] -f CRAFT /home/ldm/etc/pqact.CRAFT4"
exec    "pqact -p BZIP2/K[P-R] -f CRAFT /home/ldm/etc/pqact.CRAFT5"
exec    "pqact -p BZIP2/K[S-Z] -f CRAFT /home/ldm/etc/pqact.CRAFT6"
exec    "pqact -p BZIP2/[A-J] -f CRAFT /home/ldm/etc/pqact.CRAFT7"
exec    "pqact -p BZIP2/[L-Z] -f CRAFT /home/ldm/etc/pqact.CRAFT8"

Yeah, I cut a few out for simplicity. Interesting, though...Steve, can you comment more about this to clarify why this should be done?

Gilbert Sebenste                                                    ********
(My opinions only!)                                                  ******
Staff Meteorologist, Northern Illinois University                      ****
E-mail: sebenste@xxxxxxxxxxxxxxxxxxxxx                                  ***
web:                                      **
Twitter:                            **
Facebook:                           *

  • 2012 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the ldm-users archives: