Red Hat Summit15.4. Configuring the kdump core collector
The kdump service uses a core_collector program to capture the crash dump image. In RHEL, the makedumpfile utility is the default core collector. It helps shrink the dump file by:
- Compressing the size of a crash dump file and copying only necessary pages by using various dump levels.
- Excluding unnecessary crash dump pages.
- Filtering the page types to be included in the crash dump.
Crash dump file compression is enabled by default.
If you need to customize the crash dump file compression, follow this procedure.
- Syntax
core_collector makedumpfile -l --message-level 1 -d 31- Options
-
-c,-lor-p: specify compress dump file format by each page using either,zlibfor-coption,lzofor-loption,snappyfor-poption orzstdfor-zoption. -
-d(dump_level): excludes pages so that they are not copied to the dump file. -
--message-level: specify the message types. You can restrict outputs printed by specifyingmessage_levelwith this option. For example, specifying 7 asmessage_levelprints common messages and error messages. The maximum value ofmessage_levelis 31.
-
Prerequisites
- You have root permissions on the system.
-
Fulfilled requirements for
kdumpconfigurations and targets. For details, see Supported kdump configurations and targets.
Procedure
-
As a
root, edit the/etc/kdump.confconfiguration file and remove the hash sign ("#") from the beginning of the#core_collector makedumpfile -l --message-level 1 -d 31. Enter the following command to enable crash dump file compression:
core_collector makedumpfile -l --message-level 1 -d 31The
-loption sets the compressed file format to LZO. The-doption sets the dump level to 31. The--message-leveloption sets the message level to 1. You can also use the-c,-p, or-zoptions to specify other compression formats.See
makedumpfile(8)man page on your system for more information.
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