coredump

[kunjuttan]

Hi,
What is this coredump?How can I check it and how to clear it??

[Michal Kapalka (mikap)]

hi,

check this docu :

"Generating and Retrieving System Core Dumps"

http://docs.hp.com/en/J2237-90005/ch06s05.html

the crash dump can be generated if the system crash ( HW or SW failure ) or if you make TOC.

mikap

[Matti_Kurkela]

Michal referred to an old manual (from 1995). Since then, the terminology has changed a little.

- Core dump:
This happens most often when an application has a programming bug and tries to access a memory location it's not allowed to access. At that point, the Memory Management Unit in the processor stops the program and the OS will display an error message, like "Segmentation Fault".

If the ulimit value "coredumpsize" ("ulimit -c" command) is not set to 0, the application's memory space will be copied to a file named "core" in the current directory, and the text "(core dumped)" is added to the error message. This file will allow a programmer to find out exactly what the application was doing when the error occurred.

- Crash dump:
This used to be called "system core dump", as in Michal's document. But too often it was confused with the regular core dumps, so the name was changed. The proper name is now "crash dump". Please don't confuse ordinary core dumps with crash dumps: they are very different.

A crash dump happens when you press the TOC button on the server, or use the TC command in the GSP/MP, or if there is a serious problem at the kernel level (a bug in a driver, memory corruption that cannot be fixed by ECC, etc.).

In this situation, the system firmware takes control, and writes the contents of the system memory to a configured dump area (by default, it's the primary swap /dev/vg00/lvol2). Then the system reboots, and before activating any swap areas, the start-up scripts will copy and compress the dump into files in /var/adm/crash.

HP Support can give you a special "crashinfo" program for making a quick analysis of a crash dump. But if you send the crash dump to HP Support, they can analyze it in more detail.

MK