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Re: 20000609: LDM Capacity

Unidata Support wrote:

> ------- Forwarded Message
>
> >From: address@hidden
> >Subject: LDM Capacity
> >Organization: National Climatic Data Center
> >Keywords: 200006092008.e59K8dT14355 LDM capacity product queue
>
> What is the maximum thru put I could expect from LDM?
>
> Let me explain a little further...I want to use LDM to push files locally
> around the center here.  The number of files per day will be around 40 to
> 50 thousand and about 10Mb each.  The configuration will consist of 4 to 5
> low end workstations with 10Mbit LAN cards running LDM that will send to
> one very high end workstation with a 100Mbit LAN card running LDM.  All of
> these workstations will be on an isoloated switched network and will
> contend with no other network traffic.  I realize the number of files isn't
> a problem as I have received many hundreds of thousands of files thru
> NOAAPort, but I am concerned about the size of these files.  If the LDM
> product queue is large enough, can LDM push this much data around?
>
> Thanks,
> Alan.
>
>         ****** Signature Tag ******
>
>         National Climatic Data Center
>
> ------- End of Forwarded Message

Hi Alan,

The volume of data you describe should not be a problem, as long as you don't
try to keep too much in the queue at any one time.   500,000Mbytes/day  works
out to about 21Mbytes/hr.   Using a conservative estimate, we push at least
2Gb/day (84Mb/hr), if not more.

It might be problematic if the files tend to arrive at the same times.  With,
say, a 150Mbyte queue, you could only hold 15 10Mbyte files at one time.

I can't say much about how the capacity of the LAN cards will affect your
network.  That is well below the level of the LDM.  However, the amount of RAM
in your machine(s) would affect LDM performance since the queue is a memory
mapped file.

We have made significant improvements in the performance of the LDM, which
will be made available in an upcoming release.   So, if you were to have
problems with the current version (which I don't think will be the case), this
future version should help.

Anne

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