In this article, We will show you how to disable kdump and reclaim missing RAM on CentOS 8.
kdump is a feature of the Linux kernel that creates crash dumps in the event of a kernel crash. When triggered, kdump exports a memory image (also known as vmcore) that can be analyzed for the purposes of debugging and determining the cause of a crash.
The dumped image of main memory, exported as an Executable and Linkable Format (ELF) object, can be accessed either directly through /proc/vmcore during the handling of a kernel crash, or it can be automatically saved to a locally accessible file system, to a raw device, or to a remote system accessible over network.
In the Example below you may notice that the amount of RAM available to your server is less than advertised. This is because that the kdump being enables by default.
Disable kdump on CentOS 8
- Here is you can see the total RAM is 1.7GB when this server has 2GB of RAM allocated. which means that 300MB of RAM has been allocated to kdump.
- First, check the status of kdump as shown below.
systemctl status kdump
- Stop then disable kdump service as follows:
systemctl stop kdump systemctl disable kdump
- Edit the /etc/default/grub file to adjust the conf in the kernel.
- Then change crashkernel=auto value to crashkernel=no as shown in the below screenshot then save and quit.
- Update the grub conf file.
grub2-mkconfig -o /boot/grub2/grub.cfg
- Then reboot the system.
- The last step is to check the current RAM
You will see the missing 300MB of RAM has now been added to the RAM.
In this guide, we illustrated how to disable kdump and reclaim Missing RAM On CentOS 8.