asked on

swaping mount points and preserving data

My project at work just got a hand-me-down debian box. Everything on it is in fine working order but I need to change the mount point of one of the drives.

The drives are set up thusly:
/dev/hdd1 - mounted on /
/dev/hdc1 - mounted on /home

In the machine's previous like it had a lot of user files so having almost half of it's storage dedicated to the home directory made sense. My needs for are different, however, and I would like to have hdc1 mounted on /var/lib/mysql since most of the machines job is handling large databases.

Can someone please walk me through, step by step, the best way to change the mount location from /home to /var/lib/mysql on hdc1 without changing any of the files in either directory? I'm pretty new to the world of *nix so I need to have it explained clearly. If it matters the machine is running Debian 3.1r1.

Thank you in advance.

wesly_chen

First, make sure noone else login to that system.
As root,
umount /home
mkdir /var/lib/mysql

Then edit /etc/fstab and change the following line
/dev/hdc1 /home .....
to
/dev/hdc1 /var/lib/mysql .....

Then
mount /var/lib/mysql

bishma

ASKER

Sorry, I forgot to mention that /home and /var/lib/mysql already has a fair amount of stuff in each them. So it I do it this way does the data get transfered? I want every thing that's in /home to end up on hda1 and everything that's in /var/lib/mysql to end up on hdc1 with their ownership and permissions intact.

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wesly_chen

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bishma

ASKER

Worked perfectly and was exactly what I was looking for. Thank you for your help wesly_chen.

slyong

Hi,

wesly_chen, init 0 is to halt the system. init 1 is more like it. I suggest you do this:

1. First move the home directory...

1.1 As root, go to Single User Mode
# init 1

1.2 Make a directory /home2 which will resides in hdd1 and copy the data from /home to /home2 (use copy so that you won't lose data)
# mkdir /home2
# cp -R /home/* /home2

1.3 Unmount the /home from hdc1 and edit the fstab to disable mounting /home on hdc1 on boot
# umount /home
edit /etc/fstab and add a # infront of the line that contains /dev/hdc1

1.4 Now move the files from /home2 back to /home and delete the /home2 directory afterwards
# mv /home2/* /home
# rmdir /home2

1.5 Time to reboot and check if you system still working properly
# init 6

If you are fine until this steps, send a tinker back into EE, we will move forward from there. Otherwise, we have to roll back what we have done.

wesly_chen

Thanks slyong for the correction. My brain didn't work well at that time.