This sounds like a link MTU size problem. Try a "ping -s 1500" between the
two machines, and see if that works.
It's likely that something is set to do jumbo frames (>1500 byte MTU) and
something in the middle is limiting that to the standard 1500 byte MTU
size. (or something like 1500 byte MTU size on a link that has VLAN tags
or VPLS headers).
Patrick Finnegan
Data Center Architect
Research Computing
Purdue University
On Tue, Feb 16, 2021 at 11:52 AM Karen Cooper - NOAA Affiliate via
ldm-users <ldm-users@xxxxxxxxxxxxxxxx> wrote:
> tl;dr -- LDM setup which worked fine last week, now will not send/receive
> any files larger than 1292 bytes.
>
> Full story:
> We get data via LDM from another system. This setup/connection was
> working fine until last week. As far as we know, no changes were made --
> but obviously something has changed, because now we can't get data.
>
> Both ends are running ldm-6.13.11, which is recent and has been working
> well (except for pqact issues, which don't apply here).
>
> I see connectivity at both ends, and I have restarted and rebuilt the
> queues on both ends multiple tiles during troubleshooting.
>
> I have enabled traffic both ways, and can ldmping and run notifyme against
> the other machines queue(s).
>
> Interestingly enough the issue seems to have something to do with
> filesize. In my testing I tried using ldmsend to send files to the
> downstream server. I have an "accept" line there, and I *AM* able to send
> files* IF* they are <1293 bytes. The downstream server receives data
> from many other servers, and many of the files it receives are larger than
> 1293 bytes.
>
> Interestingly, smaller files make it through, but are taking a
> significantly long time. For instance a file of 1274 bytes can take more
> than a minute.
>
> When trying to send the larger file, there is nothing in the downstream
> logs, but the upstream logs show:
>
> 20210216T163901.154847Z dontpanic.nssl.noaa.gov(feed)[20925]
> up6.c:up6_run:445NOTE Starting Up(6.13.11/6): 20210216162900.110949
> TS_ENDT {{EXP, "/home/operator/ALAtest"}},
> SIG=d40ffc815fd74a96c2d7c726dc7012d3, Primary
> 20210216T163901.154950Z dontpanic.nssl.noaa.gov(feed)[20925]
> up6.c:up6_run:448NOTE topo: dontpanic.nssl.noaa.gov {{EXP, (.*)}}
> 20210216T164000.271093Z 140.172.25.37[20982]ldmd.c:cleanup:192NOTE Exiting
> 20210216T164001.213937Z dontpanic.nssl.noaa.gov(feed)[20925]
> ldmd.c:cleanup:192NOTE Exiting
>
> I tried setting up a second downstream system, but had the same results.
>
> I have also tried using ldmsend to send data, but again, the small files
> make it through, but larger packets fail. In verbose mode for ldmsend I
> see:
>
> ldmsend -xxx -h dontpanic.nssl.noaa.gov ALAtestfile7
> 20210216T164634.300292Z ldmsend[21540] error.c:err_log:236
> INFO Resolving dontpanic.nssl.noaa.gov to 140.172.25.37
> took 0.000755 seconds
> 20210216T164634.329557Z ldmsend[21540] ldmsend.c:main:437
> DEBUG version 6
> 20210216T164634.359151Z ldmsend[21540] ldmsend.c:ldmsend:281
> INFO Sending ALAtestfile7, 1293 bytes
> 20210216T164634.359234Z ldmsend[21540]
> LdmProxy.c:my_hereis_6:549 DEBUG Sending file via HEREIS_6
> 20210216T164734.361874Z ldmsend[21540]
> LdmProxy.c:getStatus:68 ERROR NULLPROC_6 failure to host "
> dontpanic.nssl.noaa.gov": RPC: Unable to recei
> ve; errno = Connection reset by peer
> 20210216T164734.361940Z ldmsend[21540] ldmsend.c:ldmsend:309
> ERROR Couldn't flush connection
> 20210216T164734.362006Z ldmsend[21540] ldmsend.c:cleanup:82
> ERROR Message-queue isn't empty
>
>
>
> --
> *"Outside of a dog, a book is a man's best friend. Inside of a dog, it's
> too dark to read."*
> *--Groucho Marx*
>
> -------------------------------------------
> Karen.Cooper@xxxxxxxx
>
> Phone#: 405-325-6456
> Cell: 405-834-8559
> National Severe Storms Laboratory
>
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