Customize Crash-dump-manager¶
The Linux kernel can be configured to perform a crash dump and reboot in response to specific serious events. A crash dump event produces a crash dump report with bundle of files that represent the state of the kernel at the time of the event, which is useful for post-event root cause analysis.
The kernel directs the new crash dump bundles to /var/crash/<dated dump bundle>.
Crash dump bundles are quite large and they can fill up their target filesystem.
The purpose of crash-dump-manager service is to prevent crash dumps from
filling up the root filesystem by compressing the crash bundles found in
/var/crash and moving it to /var/log/crash. The first bundle is compressed as
vmcore_first.tar and preserved. Subsequent crash bundles are saved as
vmcore_<date>.tar.
The status of the crash-dump-manager can be checked by running the following command:
% sudo systemctl status crash-dump-manager
crash-dump-manager.service - Crash Dump Manager
Loaded: loaded (/lib/systemd/system/crash-dump-manager.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Mon 2023-09-18 23:08:10 UTC; 14s ago
Main PID: 1328880 (code=exited, status=0/SUCCESS)
CPU: 22ms
Change the Default Crash-dump-manager Configuration¶
About this task
The crash-dump-manager service uses four parameters in order to customize its behavior. You can change the parameter values using service-parameters. The editable parameters and their default values are as follows:
Maximum Files
Number of saved crash dump files in crash dump file system (/var/log/crash).
Default: 4
Maximum Size
Limits the maximum size of an individual crash dump file. Support for unlimited.
Default: 5GiB
Maximum Used
Limits the maximum storage used by saved crash dump files. Support for unlimited.
Default: Unlimited
Minimum Available
Limits the minimum available storage on the crash dump file system. Default: 10% of crash dump file system size Minimum: 1GiB
Configuration Parameters Units
When configuring the Maximum Size, Maximum Used, and Minimum Available
parameters, you have the flexibility to specify the units of measurement. These
parameters accept integer/float values followed by the unit of measurement,
that can be written in two primary forms: units based on the metric system
(decimal) and units based on the binary system (binary prefixes).
Decimal units (metric system)
K: Represents kilobytes, where 1 KB is equal to 1,000 bytes.
M: Represents megabytes, where 1 MB is equal to 1,000,000 bytes.
G: Represents gigabytes, where 1 GB is equal to 1,000,000,000 bytes.
T: Represents terabytes, where 1 TB is equal to 1,000,000,000,000 bytes.
Example:
5K represents 5 kilobytes (1 KB = 1,000 bytes).
5M represents 5 megabytes (1 MB = 1,000,000 bytes).
5G represents 5 gigabytes (1 GB = 1,000,000,000 bytes).
5T represents 5 terabytes (1 TB = 1,000,000,000,000 bytes).
Binary units (binary prefixes)
Ki: Represents kibibytes, where 1 KiB is equal to 1,024 bytes.
Mi: Represents mebibytes, where 1 MiB is equal to 1,048,576 bytes.
Gi: Represents gibibytes, where 1 GiB is equal to 1,073,741,824 bytes.
Ti: Represents tebibytes, where 1 TiB is equal to 1,099,511,627,776 bytes.
Example:
5Ki represents 5 kibibytes (1 KiB = 1,024 bytes).
5Mi represents 5 mebibytes (1 MiB = 1,048,576 bytes).
5Gi represents 5 gibibytes (1 GiB = 1,073,741,824 bytes).
5Ti represents 5 tebibytes (1 TiB = 1,099,511,627,776 bytes).
Unlimited
Additionally, the Maximum Size and Maximum Used parameters support the special value
unlimited. When the parameter value is set tounlimited, there are no imposed restrictions on the size or storage usage.
Prerequisites
Ensure that you have sufficient storage available on the host’s log filesystem. For more information about adjusting the storage size, see Resize Filesystems on a Host.
Procedure
Add a crash dump service parameter.
~(keystone_admin)]$ system service-parameter-add platform crash dump <parameter>=<value>
Modify an existing crash dump service parameter.
~(keystone_admin)]$ system service-parameter-modify platform crashdump <parameter>=<value>
Delete an existing crash dump service parameter.
~(keystone_admin)]$ system service-parameter-delete <uuid>
Note
When a parameter is deleted, its value will be reset to the default value.
Where, <parameter> can be one of these: max_files, max_size, max_used, min_available.
Example:
The following example adds Maximum Files, Maximum Size, Maximum Used, and Minimum Available.
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-add platform crashdump max_files=6
+-------------+--------------------------------------+
| Property | Value |
+-------------+--------------------------------------+
| uuid | 3f5d8bc0-26cc-43b5-aeb6-d6a5b5b27035 |
| service | platform |
| section | crashdump |
| name | max_files |
| value | 6 |
| personality | None |
| resource | None |
+-------------+--------------------------------------+
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-add platform crashdump max_size=unlimited
+-------------+--------------------------------------+
| Property | Value |
+-------------+--------------------------------------+
| uuid | 164b5630-9125-4482-b08d-5b5b80d25e14 |
| service | platform |
| section | crashdump |
| name | max_size |
| value | unlimited |
| personality | None |
| resource | None |
+-------------+--------------------------------------+
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-add platform crashdump max_used=10G
+-------------+--------------------------------------+
| Property | Value |
+-------------+--------------------------------------+
| uuid | f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79 |
| service | platform |
| section | crashdump |
| name | max_used |
| value | 10G |
| personality | None |
| resource | None |
+-------------+--------------------------------------+
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-add platform crashdump min_available=4,5Gi
+-------------+--------------------------------------+
| Property | Value |
+-------------+--------------------------------------+
| uuid | da4af8a9-0a19-41d7-9f70-e803e312925c |
| service | platform |
| section | crashdump |
| name | min_available |
| value | 4,5Gi |
| personality | None |
| resource | None |
+-------------+--------------------------------------+
If you need to modify or delete any parameter, perform the following:
List the currently configured service parameters.
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-list | grep crashdump | 3f5d8bc0-26cc-43b5-aeb6-d6a5b5b27035 | platform | crashdump | max_files | 6 | None | None | | 164b5630-9125-4482-b08d-5b5b80d25e14 | platform | crashdump | max_size | unlimited | None | None | | f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79 | platform | crashdump | max_used | 10G | None | None | | da4af8a9-0a19-41d7-9f70-e803e312925c | platform | crashdump | min_available | 4,5Gi | None | None |
Update it or delete it using the UUID.
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-modify platform crashdump max_used='unlimited' +-------------+--------------------------------------+ | Property | Value | +-------------+--------------------------------------+ | uuid | f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79 | | service | platform | | section | crashdump | | name | max_used | | value | unlimited | | personality | None | | resource | None | +-------------+--------------------------------------+
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-delete f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79 Deleted service parameter: f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79
List the service-parameter to confirm the new values.
[sysadmin@controller-0 ~(keystone_admin)]$ system service-parameter-list | grep crashdump | 164b5630-9125-4482-b08d-5b5b80d25e14 | platform | crashdump | max_size | unlimited | None | None | | 3f5d8bc0-26cc-43b5-aeb6-d6a5b5b27035 | platform | crashdump | max_files | 6 | None | None | | f2a6d3b4-0b9f-40d9-89b1-4e06d425cf79 | platform | crashdump | max_used | 10G | None | da4af8a9-0a19-41d7-9f70-e803e312925c | platform | crashdump | min_available | 4,5Gi | None | None |
