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Re: CONDUIT feed timing

Pete,

In pushing the queing lag time from the NWS computer queueing the data
to the NWS computer doing the data insertion, some of the latency is
now in the LDM queue as the volume you are receiving is increased
into a shorted time window- whereas before it was all in the insertion.

I agree that the parallel insertion is at some expense of the early
files since the slug of insertion starts slowing that down and
we'll have to see if we can optimize the insertion.

Steve Chiswell
Unidata User Support





On Fri, 2005-01-07 at 13:53, Pete Pokrandt wrote:
> In a previous message to me, you wrote: 
> 
>  >
>  >Jerry,
>  >
>  >Yesterday at 1830Z we implemented a parallel queueing scheme at the
>  >NWS that we hope will improve the timeliness of data being ingected into
>  >the CONDUIT data stream. Any feedback you can provide on how
>  >this affects your reception would be greatly appreciated.
>  >
>  >Since data will be inserted in parallel, you will notice that multiple 
>  >model runds and forecast times will probably be interspersed where
>  >previously they had been serialized.
>  >
>  >I watched the 00Z GFS last night, and the posting gap between f084 and
>  >f132 was matched on the FTP server at 0422Z and later at 0509Z, the
>  >other grids were posted to the NWS servers, so all appears to be
>  >behaving correctly on this end.
>  >
>  >Steve Chiswell
>  >Unidata User Support
> 
> Steve,
> 
> Since the parallel queueing scheme was implemented, I have noticed two
> things, both are problematic.
> 
> 1) The lag goes way up since so much more data is being inserted into
> the queue in a shorter amount of time. I was getting lag times of 3000-4000
> seconds in peak gfs times.  I moved my ldm queue on f5 to a faster disk, and
> that helped, but it's still getting up to 300-400 seconds.
> 
> 2) The biggest problem I see, is that now it takes MUCH longer for the
> early hours of a forecast run to complete.  Most of my model plotting
> scripts and all of our real-time mesoscale modelling efforts here
> take advantage of the fact that an entire model run doesn't need to be
> complete before we can start.  Since the parallel queueing was enabled,
> the 00 hour forecast of the eta model for example, takes over an hour
> to get here, where previously it was taking maybe 5 minutes.
> 
> If this is how it's going to be, I'd much prefer the old serial ingest,
> or maybe some kind of blend, so the first 12 hours or so (or 48 or 
> whatever) of a model run can get priority. 
> 
> It really hurts us to have the 00 hour forecast complete around the 
> same time as the later forecasts, even if the entire model run gets 
> in faster as a result.
> 
> For what it's worth.
> 
> Pete
> 
> 
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