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

[LDM #ZOC-298338]: Missing data problems

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 Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated.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 #ZOC-298338]: Missing data problems
  • Date: Fri, 15 Jun 2007 13:22:51 -0600
Lou,

> Just out of curiousity, I remember that in years past when I restarted
> the ldm process a "ldmadmin watch" spewed data immediately.  It seems to
> take quite a while now.

How long is "a while"?  Try restarting your LDM and tailing
the new LDM log file.  Then do an "ldmadmin watch" and see
if something in the log file corresponds with the "watch"
output.

> I've put the fix "(.*)" in for one of our servers, but I'm still not
> sure how to know if the problem is occurring or truly why it would be.
> If the ldm process were switching between the two sporadically then how
> could we be receiving all of the sites.  Remember we get only one region
> per feed (to my knowledge) so if it were only using one and not the
> other, we should have a region down on each box.

A downstream LDM will switch to PRIMARY mode if it becomes
the primary mechanism by which data-products are inserted
into the product-queue.  In making this comparison, it
knows how many other downstream LDM-s are requesting the
same data.  Similarly, a downstream LDM will switch to 
ALTERNATE mode if it is no longer the primary mechanism by
which its data-products are being inserted into the product-
queue.

In your case, the downstream LDM that was in ALTERNATE mode
was, nevertheless, still inserting its received products
into the queue because the queue didn't already contain
those products.  The net effect is to slow down one of the
connections and risk loosing data.

> It would still be nice to have some indicator of the correct file size
> versus the size that NCDC has been receiving from our feed.  If you have
> any thoughts on this please let me know.  Until them I'm having NCDC
> keep an eye out to see if this fix on ldm1 clears up any problems with
> the regions it feeds (eastern & southern).

I'm not sure what you mean by "correct file size".  If you want to
know whether or not NCDC is receiving all the data-products that
it should, then search your LDM log file for the message "Data-product
with signature %s wasn't found in product-queue".  This will mean
that the upstream LDM that logged the message was unable to locate
the last data-product that was received by the downstream LDM at
the remote site.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: ZOC-298338
Department: Support LDM
Priority: Urgent
Status: On Hold