kexec-tools/kdumpctl.8
Kairui Song a9fda5c885 kdumpctl: Add kdumpctl estimate
Resolves: bz1951415
Upstream: fedora
Conflict: none

commit e9e6a2c745
Author: Kairui Song <kasong@redhat.com>
Date:   Thu Apr 22 03:27:10 2021 +0800

    kdumpctl: Add kdumpctl estimate

    Add a rough esitimation support, currently, following memory usage are
    checked by this sub command:

    - System RAM
    - Kdump Initramfs size
    - Kdump Kernel image size
    - Kdump Kernel module size
    - Kdump userspace user and other runtime allocated memory (currently
      simply using a fixed value: 64M)
    - LUKS encryption memory usage

    The output of kdumpctl estimate looks like this:
      # kdumpctl estimate
      Reserved crashkernel:    256M
      Recommanded crashkernel: 160M

      Kernel image size:   47M
      Kernel modules size: 12M
      Initramfs size:      19M
      Runtime reservation: 64M
      Large modules:
          xfs: 1892352
          nouveau: 2318336

    And if the kdump target is encrypted:
      # kdumpctl estimate
      Encrypted kdump target requires extra memory, assuming using the keyslot with minimun memory requirement

      Reserved crashkernel:    256M
      Recommanded crashkernel: 655M

      Kernel image size:   47M
      Kernel modules size: 12M
      Initramfs size:      19M
      Runtime reservation: 64M
      LUKS required size:  512M
      Large modules:
          xfs: 1892352
          nouveau: 2318336
      WARNING: Current crashkernel size is lower than recommanded size 655M.

    The "Recommanded" value is calculated based on memory usages mentioned
    above, and will be adjusted accodingly to be no less than the value provided
    by kdump_get_arch_recommend_size.

    Signed-off-by: Kairui Song <kasong@redhat.com>
    Acked-by: Pingfan Liu <piliu@redhat.com>

Signed-off-by: Kairui Song <kasong@redhat.com>
2021-05-20 16:08:16 +08:00

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1.2 KiB
Groff

.TH KDUMPCTL 8 2015-07-13 kexec-tools
.SH NAME
kdumpctl \- control interface for kdump
.SH SYNOPSIS
.B kdumpctl
.I COMMAND
.SH DESCRIPTION
.B kdumpctl
is used to check or control the kdump service.
In most cases, you should use
.B systemctl
to start / stop / enable kdump service instead. However,
.B kdumpctl
provides more details for debug and a helper to setup ssh key authentication.
.SH COMMANDS
.TP
.I start
Start the service.
.TP
.I stop
Stop the service.
.TP
.I status
Prints the current status of kdump service.
It returns non-zero value if kdump is not operational.
.TP
.I restart
Is equal to
.I start; stop
.TP
.I reload
reload crash kernel image and initramfs without triggering a rebuild.
.TP
.I rebuild
rebuild the crash kernel initramfs.
.TP
.I propagate
Helps to setup key authentication for ssh storage since it's
impossible to use password authentication during kdump.
.TP
.I showmem
Prints the size of reserved memory for crash kernel in megabytes.
.TP
.I estimate
Estimate a suitable crashkernel value for current machine. This is a
best-effort estimate. It will print a recommanded crashkernel value
based on current kdump setup, and list some details of memory usage.
.SH "SEE ALSO"
.BR kdump.conf (5),
.BR mkdumprd (8)