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CORE

 
Reuben M. Ordonio
Occasional Contributor

CORE

What does it mean when your server is creating a file called "core"? Is this an indication of a hardware related problem? I'm also experiencing an error that says "There is not enough memory" from time to time. Is this related to this "core" thing?
TIMTOWTDI
8 REPLIES 8
Eugeny Brychkov
Honored Contributor

Re: CORE

Usually coredumping is caused by incorrect software behavior - in your case maybe software is trying to allocate some memory, but do not track that allocation function returns 'no memory available' and tries to write to 'null' area - causing coredumping ('memory page protection fault' in windows...).
If there's a hardware issue, server crashdumps and reboots
Eugeny
Michael Tully
Honored Contributor

Re: CORE


Basically a core dump from an application is what was in memory as a page fault for a particular function or program.
You can find where it comes from by:

$ what core

Hardware problems do not dump core, they may issue a panic and reboot your system.
Anyone for a Mutiny ?
Suhas_2
Regular Advisor

Re: CORE

Hi,
This problem is related to resources on the server. When a particular application is trying to allocate some memory using systems calls like "malloc" or "calloc" it is facing a problem. When this system call fails the application will dump core.
Secondly, such problem may occur because of wrong way of allocating memory in the programs. Some programs go on allocating memory but never release it, this is called as "Memory leakage", a typical solution would be to reboot the server to release the memory and tuning the application code to avoid any future incidents.

Rgds..
Suhas
Never say "Die"
Steve Steel
Honored Contributor

Re: CORE

Hi


file core


Will tell you what happened


You may need to debug it or tune your system


Please post the output.

Look in /var/adm/syslog/syslog.log at the same time as the core.


Steve Steel
If you want truly to understand something, try to change it. (Kurt Lewin)
Mark Greene_1
Honored Contributor

Re: CORE

You can use the file command to determine what process aborted (and thus created the core file).

You can also use the strings command to see what's in the core file:

strings core |pg

Common causes include hardware problems, telnet or socket sessions dropping without properly shutting down the associated processes on the HP side, and there's a couple of SAM bugs that will dump core if you aren't up-to-date with your patches.

HTH
mark
the future will be a lot like now, only later
Michael Murphy_2
Frequent Advisor

Re: CORE

I agree with running a the "file" command on the core to see which binary is creating it. Also, examine the size of the core. Compare it to the value of maxdsize. If they are around the same size, the exec is reaching the memory limit in your kernel. Bump up the kernel param and re-run - but be aware that if the process has a memory leak it will get the error again - watch the memory usage with ps.
Donny Jekels
Respected Contributor

Re: CORE

you can also analyse the core dump

#strings core | more

this would give you a closer idea og what cuased the core dump. don't try to go way deep into the file. usually the answer is within the 1st couple of lines.

peace
Donny
"Vision, is the art of seeing the invisible"
Dario_1
Trusted Contributor

Re: CORE

Hi!

Check this post. Paula gives a very nice explanation about how to check a core file.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x4f1f9607df6ed711abdc0090277a778c,00.html

Regards,

Dario