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[LDM #GBJ-864447]: Couldn't lock database for writing errors

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  • Subject: [LDM #GBJ-864447]: Couldn't lock database for writing errors
  • Date: Wed, 06 Apr 2016 10:54:31 -0600
Hi Rosie and Steve,

re: McIDAS deleting LDM shared memory segments?

> Yes McIDAS is installed.  A few cronjobs use it but a McIDAS session is
> not kept up on it.

I think Steve was substituting 'McIDAS' when he really meant 'GEMPAK'.
The reason for the comment is that some sites that run GEMPAK implemented
draconian procedures for cleaning up shared memory segments and semafores.
Since McIDAS itself cleans up the share memory segments that it creates,
McIDAS-related shared memory expunging would have to have been done by
someone implementing a procedure to clear out shared memory segments.

re:
> We have never seen this happen before..

I have seen this in the CentOS VM in which we are running our UNIWISC
and FNEXRAD image creation processing in AWS.  My "solution" for that
installation was to drop back to LDM-6.8.1 since it was a good, stable
release in the pre-shared memory segment days.  That being said, however,
newer attempts of running a current LDM in CentOS 6.6/7.1 VMs in AWS
have been entire successful.  I have not figured out what is different
on or original AWS VM.

re:
> and why would it start after an ldm restart?

It shouldn't as the shared memory segment will be created at LDM
startup.

re:
> Suggestions for how to  prevent this?

The problem would need to be completely understood before proposing
a procedure for preventing it.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: GBJ-864447
Department: Support LDM
Priority: Normal
Status: Open