6.2. Build the LVM 1 kernel module
To use LVM 1 you will have to build the LVM 1 kernel module
(recommended), or if you prefer rebuild the kernel with the
LVM 1 code statically linked into it.
Your Linux system is probably based on one of the popular
distributions (eg., Red Hat, SuSE, Debian) in which case it
is possible that you already have the LVM 1 module. Check
the version of the tools you have on your system. You can do
this by running any of the LVM command line tools with the
'-h' flag. Use pvscan -h if you don't
know any of the commands. If the version number listed at
the top of the help listing is LVM 1.0.8, use your current setup and avoid the
rest of this section.
6.2.1. Building a patch for your kernel
In order to patch the linux kernel to support LVM 1.0.8, you must
do the following:
Unpack LVM 1.0.8
# tar zxf lvm_1.0.8.tar.gz
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Enter the root directory of that version.
Run configure
You will need to pass the option
--with-kernel_dir to configure if your
linux kernel source is not in
/usr/src/linux.
(Run ./configure --help to see all the
options available)
Enter the PATCHES directory
Run 'make'
You should now have a patch called
lvm-1.0.8-$KERNELVERSION.patch in the
patches directory. This is the LVM kernel patch referenced
in later sections of the howto.
Patch the kernel
# cd /usr/src/linux ; patch -pX < /directory/lvm-1.0.8-$KERNELVERSION.patch
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6.2.2. Building the LVM module for Linux 2.2.17+
The 2.2 series kernel needs to be patched before you can start
building, look elsewhere for instructions on how to patch your
kernel.
Patches:
rawio patch
Stephen Tweedie's raw_io patch which can be found at
https://www.kernel.org/pub/linux/kernel/people/sct/raw-io
lvm patch
The relevant LVM 1 patch which should be built out
of the PATCHES sub-directory of the LVM
distribution. More information can be found in
Section 6.2.1, Building a patch
for your kernel.
Once the patches have been correctly applied, you need to make sure
that the module is actually built, LVM 1 lives under the block
devices section of the kernel config, you should probably request
that the LVM /proc information is compiled as well.
Build the kernel modules as usual.
6.2.3. Building the LVM modules for Linux 2.4
The 2.4 kernel comes with LVM 1 already included although
you should check at the Sistina web site for updates,
(eg. v2.4.9 kernels and earlier must have the latest LVM 1 patch applied ).
When configuring your kernel look for LVM 1 under Multi-device support (RAID and
LVM). LVM 1 can be compiled into the kernel or as
a module. Build your kernel and modules and install then
in the usual way. If you chose to build LVM as a module it
will be called lvm-mod.o
If you want to use snapshots with ReiserFS, make sure you apply the
linux-2.4.x-VFS-lock patch (there are copies
of this in the
LVM/1.0.8/PATCHES directory.)
6.2.4. Checking the proc file system
If your kernel was compiled with the /proc file system (most are)
then you can verify that LVM is present by looking for a /proc/lvm
directory. If this doesn't exist then you may have to load the
module with the command
If /proc/lvm still does not exist then check
your kernel configuration carefully.
When LVM is active you will see entries in
/proc/lvm for all your physical volumes,
volume groups and logical volumes. In addition
there is a "file" called
/proc/lvm/global which gives a summary
of the LVM status and also shows just which version of the LVM
kernel you are using.
