What is "crashkernel=X@Y" in /etc/grub.conf?

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Issue

What is "crashkernel=X@Y" in /etc/grub.conf

Environment

Red Hat Enterprise Linux

Resolution

"crashkernel=X@Y" is a kernel parameter for Kdump.

Kdump requires some memory reservation for the second kernel(capture kernel).

When kdump is enabled, (physical memory - X) will be allocated.

Kdump is disabled:

# uname -...

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