The original version of this article was first published on IBM
developerWorks, and is property of Westtech Information Services. This
document is an updated version of the original article, and contains
various improvements made by the Gentoo Linux Documentation team.
This document is not actively maintained.
Partitioning in action, Part 1
The partition /home is one of the most-often-moved partitions.
Sometimes, all the space in /home becomes exhausted, and an
additional hard drive is required. Other times, /home is set up as
part of the root partition, and it may need to be moved to improve performance
or facilitate backup. Whatever the case, I'll show you how to move
/home safely and efficiently.
The following technique describes how to move a partition(s). Although this
technique is designed so that you can "back out" of a failed partition move, it
doesn't protect against user error. In other words, any time that you format
partitions or copy large numbers of files, there's a possibility that you will
type the wrong thing, causing lots of data to be destroyed. For this reason,
it's highly recommended that you take appropriate steps to back up all
critical files before proceeding.
Now that you're prepared, we're ready to start moving /home. The
exact steps you will take depend on whether /home currently
resides on its own separate partition, or whether it is located on the root
partition. Keep this in mind as we go through the steps (I'll make notes where
necessary). Right now, if you are moving /home to a new hard
drive, it should be physically installed in your system.
If you are moving /home to an existing partition (it doesn't need
to be ext2, as long as the target primary or extended partition exists), you
can proceed to step 2.
Create a new partition, if necessary
If the new partition doesn't exist yet, you'll need to create it using
cfdisk (preferred) or fdisk. If the partition doesn't reside on
your first drive, remember to specify the name of the device as the first
argument to cfdisk or fdisk. After creating the appropriate
primary or extended partition, you should reboot so that the partition table
can be reread correctly. This is the only time you will need to reboot the
Create a filesystem on the new partition
To create a filesystem on the new partition, first make sure you know the exact
device name for the new partition (for example, /dev/sda5). If
you're not sure of the exact device name, stop now and double-check! Then type
the following, as root:
Code Listing 2.1: Creating the filesystem
# mkfs.ext2 /dev/???
In the above and following code samples, ??? should be replaced
with the target partition name. After executing this command, the target
partition will contain an empty ext2 filesystem.
Mount the new filesystem in /mnt
Create a directory called /mnt/newpart, and then mount the new
Code Listing 3.1: Mounting the partition
# mount /dev/??? /mnt/newpart
Drop to single-user mode
I delayed this step as long as possible to maximize system availability, but we
now must drop into single-user mode, and copy files from /home to
/mnt/newpart. You shouldn't have any files open in
/home, and entering single-user mode eliminates this possibility:
Code Listing 4.1: Entering single user mode
# init 1
If prompted, enter the root password to perform system maintenance. You should
now have a root shell.
Change directories to /home and copy files
Type the following:
Code Listing 5.1: Copying files
# cd /home
# cp -ax * /mnt/newpart
The cp -ax command recursively copies the contents of /home
to /mnt/newpart, preserving all file attributes, and not crossing
any mount points. After this command finishes, /mnt/newpart will
contain an exact copy of all the files and directories currently in
/home. If the old /home was on its own separate
partition (listed on a separate line in /etc/fstab), go to step 6a. Otherwise, proceed to step
Use the new partition
6a: /home on its own partition
These instructions are for systems where the old /home is already
on its own dedicated partition. If this isn't the case, see step 6b.
Unmount the old partition by typing:
Code Listing 6.1: Unmounting
# cd /
# umount /home
Then, unmount and remount the new partition:
Code Listing 6.2: Remounting the partition
# umount /mnt/newpart
# mount /dev/??? /home
Now, the new partition is available at /home and is ready to be used. We can
perform the last few steps in multiuser mode. Exit single-user mode, so that
the system is back up and running, by pressing CTRL-D.
After the system starts up normally, log in as root and edit
/etc/fstab so that /dev/??? is now mounted
automatically at /home instead of your old partition. For example,
change this line:
Code Listing 6.3: Old fstab
/dev/hda3 /home ext2 defaults 1 2
to this line:
Code Listing 6.4: New fstab
/dev/??? /home ext2 defaults 1 2
6b: /home on a shared partition
These instructions are for systems where the old /home is on a
Code Listing 6.5: Moving the directory
# cd /
# mv /home /home.old
# mkdir /home
# mount /dev/??? /home
Now, leave single user mode by pressing CTRL-D. When the system is back
up and running, edit /etc/fstab and add a line like the
Code Listing 6.6: Editing fstab
/dev/??? /home ext2 defaults 1 2
That way, your new partition will get mounted correctly the next time the
system is rebooted.
We deliberately left the old /home directory/partition behind,
just in case there were problems copying files. After verifying that the system
is running smoothly, you can either use your old /home partition
for something else, or remove the /home.old directory.
Congratulations, you've just moved /home! In my next tip, we'll
reconfigure a system so that /tmp and /var are on
their own shared partition. See you then.
About the author
Daniel Robbins lives in Albuquerque, New Mexico. He was the President/CEO of
Gentoo Technologies Inc., the Chief Architect of the Gentoo Project and is a
contributing author of several books published by MacMillan: Caldera OpenLinux
Unleashed, SuSE Linux Unleashed, and Samba Unleashed. Daniel has been involved
with computers in some fashion since the second grade when he was first exposed
to the Logo programming language and a potentially lethal dose of Pac Man.
This probably explains why he has since served as a Lead Graphic Artist at SONY
Electronic Publishing/Psygnosis. Daniel enjoys spending time with his wife Mary
and his new baby daughter, Hadassah. You can contact Daniel at