Just an FYI, the machine I was having problems with is less than one
year old, 20 cores, 64GB of memory. It was still dropping UDP packets
with a 15 megabit data rate. The default buffer sizes are way too
small. But it doesn't seem to be the problem here.
On Thu, Aug 21, 2014 at 09:36:13AM -0500, Gerry Creager - NOAA Affiliate wrote:
> Just a thought/suggestion. I was surprised at the results they found, but
> the procedures were well-thought-out and looked sound.
> gc
>
>
>
> On Thu, Aug 21, 2014 at 9:34 AM, Tyler Allison <tyler@xxxxxxxxxxxxxxxx>
> wrote:
>
> > Bird01 is a less than year old dell rack mount.
> >
> > -Tyler
> >
> > On Aug 21, 2014, at 9:08 AM, Gerry Creager - NOAA Affiliate <
> > gerry.creager@xxxxxxxx> wrote:
> >
> > There was an interesting discussion on a software-defined networks list
> > about the amount of CPU and memory required to handle larger and faster UDP
> > data streams. Of course, they're talking about 10gigabit and 40gigabit
> > datastreams, but if your ingest machine is a little older and might be a
> > little light on memory, this could be an element.
> >
> > gerry
> >
> >
> > On Thu, Aug 21, 2014 at 8:59 AM, Daniel Forrest <dan.forrest@xxxxxxxxxxxxx
> > > wrote:
> >
> >> Gilbert,
> >>
> >> > OK, everything is good with the new NOAAport, right? C/N of 18. Signal
> >> > strength: 76. VBER: 0. Yay! But wait...
> >> >
> >> > I am seeing a ton of these in our ldmd.log:
> >> >
> >> > Aug 21 13:00:32 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13452198 to 13452266 [skipped 67]
> >> > Aug 21 13:00:32 bird01 noaaportIngester[24645] WARN: Retrograde packet
> >> > number: previous=13452270, latest=13452230, difference=4294967336
> >> > Aug 21 13:00:32 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13452230 to 13452232 [skipped 1]
> >> > Aug 21 13:00:32 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13452232 to 13452245 [skipped 12]
> >> > Aug 21 13:00:43 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13452515 to 13452524 [skipped 8]
> >> > Aug 21 13:00:43 bird01 noaaportIngester[24645] ERROR: Missing GOES
> >> > fragment
> >> > in sequence, last 37/86751 this 46/86751
> >> > Aug 21 13:00:43 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13452524 to 13452598 [skipped 73]
> >> > Aug 21 13:00:43 bird01 noaaportIngester[24645] WARN: Retrograde packet
> >> > number: previous=13452598, latest=13452540, difference=4294967354
> >> > Aug 21 13:01:07 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13453270 to 13453274 [skipped 3]
> >> > Aug 21 13:01:07 bird01 noaaportIngester[24645] ERROR: Missing GOES
> >> > fragment
> >> > in sequence, last 115/86753 this 119/86753
> >> > Aug 21 13:01:07 bird01 noaaportIngester[24645] WARN: Gap in packet
> >> > sequence:
> >> > 13453279 to 13453283 [skipped 3]
> >> >
> >> > Is anyone else seeing this?
> >>
> >> I recently had a similar problem using the GOES-R simulator.
> >>
> >> Just a guess, but if the data is coming in via UDP and the data rate is
> >> higher than it was before then it may be a case of too little kernel
> >> buffer space. You can try this (assuming this is Linux):
> >>
> >> cat /proc/sys/net/core/rmem_max
> >> cat /proc/sys/net/core/wmem_max
> >> cat /proc/sys/net/core/rmem_default
> >> cat /proc/sys/net/core/wmem_default
> >>
> >> Save these values, if this doesn't help you can reset them.
> >>
> >> echo 16777216 >/proc/sys/net/core/rmem_max
> >> echo 16777216 >/proc/sys/net/core/wmem_max
> >> echo 16777216 >/proc/sys/net/core/rmem_default
> >> echo 16777216 >/proc/sys/net/core/wmem_default
> >>
> >> And restart LDM.
> >>
> >> If this works you can add these values to /etc/sysctl.conf.
> >>
> >> --
> >> Dan
> >>
> >> _______________________________________________
> >> ldm-users mailing list
> >> ldm-users@xxxxxxxxxxxxxxxx
> >> For list information or to unsubscribe, visit:
> >> http://www.unidata.ucar.edu/mailing_lists/
> >>
> >
> >
> >
> > --
> > Gerry Creager
> > NSSL/CIMMS
> > 405.325.6371
> > ++++++++++++++++++++++
> > ???Big whorls have little whorls,
> > That feed on their velocity;
> > And little whorls have lesser whorls,
> > And so on to viscosity.???
> > Lewis Fry Richardson (1881-1953)
> >
> > _______________________________________________
> > ldm-users mailing list
> > ldm-users@xxxxxxxxxxxxxxxx
> > For list information or to unsubscribe, visit:
> > http://www.unidata.ucar.edu/mailing_lists/
> >
> >
>
>
> --
> Gerry Creager
> NSSL/CIMMS
> 405.325.6371
> ++++++++++++++++++++++
> ???Big whorls have little whorls,
> That feed on their velocity;
> And little whorls have lesser whorls,
> And so on to viscosity.???
> Lewis Fry Richardson (1881-1953)
--
Dan
