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[LDM #TKK-421926]: LDM errors

Brian,

Every upstream LDM process updates a shared memory segment with information
on the downstream request. This is the same segment that the uldbutil(1) 
utility displays. The error messages you encountered mean that the shared
memory segment no longer exists. Someone or something deleted it --
probably with the ipcrm(1) utility.

We've seen this before with McIDAS installations. Its startup script
does a blanket ipcrm(1).

> We have a series of three LDM servers flowing GOES-R data from the BNCF to
> a test bed system in our lab.  A few weeks ago, the box in the middle was
> upgraded from RHEL 6 to RHEL 7.  Ever since then, the LDM socket between
> the middle system and the destination system drops periodically (anywhere
> from hours to days) and never restarts.  The ldmd.log from the middle
> system (RHEL 7) shows this repeated error sequence:
> 
> 20170712T120758.318287Z cpsbn4.napo.nws.noaa.gov(feed)[4339] ERROR
> semRWLock.c:435:srwl_writeLock() Invalid argument
> 20170712T120758.318311Z cpsbn4.napo.nws.noaa.gov(feed)[4339] ERROR
> semRWLock.c:435:srwl_writeLock() Couldn't lock for writing: semId=851977
> 20170712T120758.318316Z cpsbn4.napo.nws.noaa.gov(feed)[4339] ERROR
> uldb.c:1747:db_lock() Couldn't lock database for writing
> 20170712T120758.318321Z cpsbn4.napo.nws.noaa.gov(feed)[4339] ERROR
> uldb.c:2160:uldb_addProcess() Couldn't lock database
> 20170712T120758.318325Z cpsbn4.napo.nws.noaa.gov(feed)[4339] ERROR
> ldm_server.c:275:feed_or_notify() Couldn't add this process to the upstream
> LDM database
> 20170712T120758.319287Z cpsbn4.napo.nws.noaa.gov(feed)[4339] NOTE
> ldmd.c:187:cleanup() Exiting
> 
> There are no errors logged on the destination LDM.  The destination LDM is
> 6.12.14 and the RHEL 7 (middle) system is 6.13.6.  Have you seen this
> before and do you have any idea how to fix it?

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: TKK-421926
Department: Support LDM
Priority: Normal
Status: Closed
===================
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