Warning — These pages discuss older technologies.
Though the high-level concepts are still valid, some of the low-level
specifics (Linux 2.4, LILO, IDE disks, etc.) are obsolete.
You probably don't want to go through these steps verbatim on a modern system.
Migrating a Linux boot partition to RAID-1
You have experience with administering a Linux or Unix system from the
command line. You should also be comfortable with editing configuration
files using a text editor.
While following these directions it is fairly easy to
inadvertently leave your system in an unbootable state. It is
therefor highly recommended that you have a rescue boot floppy or CD
handy and that you know how to use it to bring your system back to a
bootable state. I also recommend having copies of the
Linux Bootable Business Card
You know what partitions, primary and secondary IDE buses, master and
slave drives are and are familiar with how physical devices are named (e.g.
You feel comfortable with making changes to your computer's hardware.
You have physical access to the machine that you want to convert.
You are using IDE drives on an IBM-compatible PC.
root access to the machine.
All commands mentioned in this document need to be run by
Linux is already installed on the system that you want to convert.
You are running a 2.4.0 or later kernel or are willing to upgrade to one.
The kernel used in this text is 2.4.20 but any of the
2.4.x kernels should work fine. The steps below may also work for 2.6.x
kernels but this has not been tested.
You are familiar with building a Linux kernel from source.
If you do not feel comfortable with compiling a kernel
from source, you can still use this document if your Linux distribution
supplies a kernel with the native Linux RAID-1 drivers. The drivers must
be compiled into the kernel, using modules will not work for the method
described in this document.
Your bootloader is
Your boot device is the master disk on the primary IDE bus
Your disk has a single partition containing the entire root filesystem
This technique will also work if:
You have currently have a swap partition defined and you replace it
with a swapfile.
You currently have filesystems on more than one partitition on the
boot drive. You will need to combine them into a single partition
or create separate raid arrays for each partition.
Both of these cases are straighforward to handle; see the
for more information on how to do this.
Last modified 2015-08-24
© 2005-2023 Alexander Hajnal