Moving "/" to a new disk

ceashton · 11-21-2007, 07:05 AM

Hi,

I am trying to move my root partition to a hard disk with more space, but before I go and fluff things up, I wanted make sure I have the correct approach.

Currently swap, /, /usr/local and /home are all mounted on their own partitions, but / is now rather full and needs moving to a separate disk. I've installed a new disk and formatted as ext3 using fdisk and mkfs.ext3. This new disk I have mounted under /new-disk to enable the copying of / to the new disk. Up to this point I have been following the instructions given in this Howto (http://www.tldp.org/HOWTO/Hard-Disk-Upgrade/).

Is there a reason not to use a rsync -a --exclude=some-dir-to-exclude / /new-drive command, rather than cp -a /bin /boot /other-dirs / /new-drive command?

I have come to understand that I don't want to copy /proc as this is a virtual file system containing system data, which is populated at boot time. I also don't want to copy /usr/local and /home, all of which I can specify with the --exclude= switch. Are there any other directories I shouldn't be copying? I am using Slackware 12.0 and the some of the dir aren't mentioned in the howto I am following, which I believe is quite old - but otherwise excellent to follow and explains the reasoning behind each stage. / currently contains the following dirs:

Code:

chris@dinosaur:~ $ ls -l /
total 92
drwxr-xr-x   2 root root   4096 2007-04-30 05:35 bin
drwxr-xr-x   2 root root   4096 2007-08-06 23:56 boot
drwxr-xr-x  21 root root  14120 2007-11-21 11:20 dev
drwxr-xr-x  63 root root   4096 2007-11-21 11:19 etc
drwxr-xr-x   5 root root   4096 2007-11-13 00:12 home
drwxr-xr-x   5 root root   4096 2007-07-31 19:31 lib
drwx------   2 root root  16384 2007-07-30 23:04 lost+found
drwxr-xr-x  16 root root   4096 2007-11-21 11:20 media
drwxr-xr-x  11 root root   4096 2006-09-26 04:09 mnt
drwxr-xr-x   2 root root   4096 2007-11-21 11:03 new-disk
drwxr-xr-x   3 root root   4096 2007-08-08 16:06 opt
drwxr-xr-x   2 1016 users  4096 2007-07-16 06:32 pmount
dr-xr-xr-x 101 root root      0 2007-11-21 10:38 proc
drwxr-xr-x  22 root root   4096 2007-11-17 20:34 root
drwxr-xr-x   2 root root   4096 2007-07-19 18:36 sbin
drwxr-xr-x   2 root root   4096 2007-07-30 23:13 srv
drwxr-xr-x  12 root root      0 2007-11-21 10:38 sys
drwxrwxrwt  10 root root  16384 2007-11-21 10:56 tmp
drwxr-xr-x  17 root root   4096 2005-07-29 10:44 usr
drwxr-xr-x  16 root root   4096 2007-07-26 20:15 var

So directories I believe I definitely want to copy over are:

Code:

/bin  
/boot  
/dev  
/etc  
/lib  
/lost+found  
/media  
/mnt  
/opt  
/root
/sbin  
/tmp  
/usr  
/var

Directories I definitely wouldn't are:

Code:

/home
/new-disk
/proc

Directories I am unsure about are:

Code:

/pmount
/srv  
/sys

Is this the correct method and has anybody got any suggestions on the directories I am unsure about? I've had a quick read of http://www.pathname.com/fhs/pub/fhs-2.3.html, and I'm guessing /srv should be copied.

Anyway, any help/suggestions would be gratefully received.

Chris

bigrigdriver · 11-21-2007, 07:20 AM

When I have done similar movement of parts of my system between partitions, I did it via liveCD. Boot the live cd, mount only the root partition and copy it to the new partition. That way, /home is not copied (only the folder is copied, not the contents); same applies to /proc, /usr/local, /sys and any others that are only populated on bootup, or that reside in another partition.

Before reboot, remember to edit /boot/grub/menu.lst and /etc/fstab to show the new partition for /.

jschiwal · 11-21-2007, 07:26 AM

I don't think you need to copy /sys. Copying /tmp would be pointless. Also, lost & found is created during formatting. Don't copy it either. The /mnt and /media directories are used to mount other filesystems or devices. You do want to create /sys, /mnt, /media and /tmp on the destination however. For /tmp, change the permissions giving everyone full permissions and setting the sticky bit.
sudo chmod a=rwxt /new-drive/tmp

Even though you don't want to copy the contents of /home and /usr/local, you need to create these directories so that you have a place to mount these partitions on.

ceashton · 11-21-2007, 08:38 AM

Thanks for the quick replies. I'm just trying it now, I'll report back my success!

Kind regards,

Chris

ceashton · 11-21-2007, 12:37 PM

Thanks for the help. The actual command I used to copy, was:

Code:

rsync -av --exclude=/home/* --exclude=/lost+found/* --exclude=/mnt/spare/* --exclude=/new-disk --exclude=/proc/* --exclude=/sys/* --exclude=/usr/local/* / /new-disk/ 1>/rsync.log 2>/rsync.log.error &

which seems to have worked fine, once I'd correctly configured fstab and lilo as per the Howto in my initial post.

Once again, thanks for the replies I received - you were spot on!

Chris