the system panics). The system kernel's memory image is preserved across
the reboot and is accessible to the dump-capture kernel.
-You can use common Linux commands, such as cp and scp, to copy the
+You can use common commands, such as cp and scp, to copy the
memory image to a dump file on the local disk, or across the network to
a remote system.
2) Download the kexec-tools user-space package from the following URL:
-http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/kexec-tools-testing.tar.gz
+http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/kexec-tools.tar.gz
-This is a symlink to the latest version, which at the time of writing is
-20061214, the only release of kexec-tools-testing so far. As other versions
-are made released, the older onese will remain available at
-http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/
+This is a symlink to the latest version.
-Note: Latest kexec-tools-testing git tree is available at
+The latest kexec-tools git tree is available at:
-git://git.kernel.org/pub/scm/linux/kernel/git/horms/kexec-tools-testing.git
+git://git.kernel.org/pub/scm/linux/kernel/git/horms/kexec-tools.git
or
-http://www.kernel.org/git/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=summary
+http://www.kernel.org/git/?p=linux/kernel/git/horms/kexec-tools.git
+
+More information about kexec-tools can be found at
+http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/README.html
3) Unpack the tarball with the tar command, as follows:
- tar xvpzf kexec-tools-testing.tar.gz
+ tar xvpzf kexec-tools.tar.gz
4) Change to the kexec-tools directory, as follows:
- cd kexec-tools-testing-VERSION
+ cd kexec-tools-VERSION
5) Configure the package, as follows:
2) Or use the system kernel binary itself as dump-capture kernel and there is
no need to build a separate dump-capture kernel. This is possible
- only with the architecutres which support a relocatable kernel. As
- of today i386 and ia64 architectures support relocatable kernel.
+ only with the architectures which support a relocatable kernel. As
+ of today, i386, x86_64, ppc64 and ia64 architectures support relocatable
+ kernel.
Building a relocatable kernel is advantageous from the point of view that
one does not have to build a second kernel for capturing the dump. But
Dump-capture kernel config options (Arch Dependent, ppc64)
----------------------------------------------------------
-* Make and install the kernel and its modules. DO NOT add this kernel
- to the boot loader configuration files.
+1) Enable "Build a kdump crash kernel" support under "Kernel" options:
+
+ CONFIG_CRASH_DUMP=y
+
+2) Enable "Build a relocatable kernel" support
+
+ CONFIG_RELOCATABLE=y
+
+ Make and install the kernel and its modules.
Dump-capture kernel config options (Arch Dependent, ia64)
----------------------------------------------------------
- No specific options are required to create a dump-capture kernel
- for ia64, other than those specified in the arch idependent section
+ for ia64, other than those specified in the arch independent section
above. This means that it is possible to use the system kernel
as a dump-capture kernel if desired.
any space below the alignment point will be wasted.
+Extended crashkernel syntax
+===========================
+
+While the "crashkernel=size[@offset]" syntax is sufficient for most
+configurations, sometimes it's handy to have the reserved memory dependent
+on the value of System RAM -- that's mostly for distributors that pre-setup
+the kernel command line to avoid a unbootable system after some memory has
+been removed from the machine.
+
+The syntax is:
+
+ crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset]
+ range=start-[end]
+
+ 'start' is inclusive and 'end' is exclusive.
+
+For example:
+
+ crashkernel=512M-2G:64M,2G-:128M
+
+This would mean:
+
+ 1) if the RAM is smaller than 512M, then don't reserve anything
+ (this is the "rescue" case)
+ 2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M
+ 3) if the RAM size is larger than 2G, then reserve 128M
+
+
+
Boot into System Kernel
=======================
is called inside interrupt context or die() is called and panic_on_oops is set,
the system will boot into the dump-capture kernel.
-On powererpc systems when a soft-reset is generated, die() is called by all cpus
+On powerpc systems when a soft-reset is generated, die() is called by all cpus
and the system will boot into the dump-capture kernel.
For testing purposes, you can trigger a crash by using "ALT-SysRq-c",
Vivek Goyal (vgoyal@in.ibm.com)
Maneesh Soni (maneesh@in.ibm.com)
-
-Trademark
-=========
-
-Linux is a trademark of Linus Torvalds in the United States, other
-countries, or both.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff