Methods to partly clone a device

[toddbailey]

Hi All,


I have a disk partition (/) want to copy to a smaller drive.
I checked and it appears the dd command won't work, it wants a larger destination device.

I want to go the other direction, I basically want to copy the / partition off a 300 gb drive to a 30 gig drive.
the actual space used is in the order of 20-25 gb

I'm was planning to boot using a thumb drive so the source and destination won't be mounted unless necessary

The destination device is partitioned with a boot and / already,
I don't know if a cp command will work

I'm ok over writing the destination device completely but think it's un-necessary, both devices have the same version/archit. installed and I just need to overwrite the existing / partition from the source

Is tar and rsync the only methods to use? which is the better/ easier to utilize?


thanks

[jpollard]

Personally, I think tar is better. But that is my opinion, and there have been good results reported with rsync.

[toddbailey]

I've been googling the topic and can't I just use a cp -pr /source /destination or am I missing something?

[stevea]

Yes you can use "cp -pr". Just make sure you create the new FS with the correct parameters.

[DrHappyAngry]

Well if you're planning on booting from that other drive you'll need to edit the fstab in the new install, as well as install the bootloader to that drive. I think it's just "grub-instal /dev/sdX" where sdX is the drive you want to install to. To find the UUID of the new partitions on the new drive run "blkid" and change the uuid for / to the one you got from blkid.

[toddbailey]

So much for "easy" I (finally) got rsync to copy, and after a few iterations, I get to a boot sequence only to fail with a message

unable to find root partition, sleeping for ever, which considering the time I think I'll take the hint and try again tomorrow


The command I used was rsync -avHx --delete source destination

I edited the fstab and updated the UUID to the values reported from ls -l /dev/disks/by-uuid taked from usb key
when that didn't work I tried to state by device /dev/sda1 /boot & /dev/sda2 / etc.

---------- Post added at 12:24 AM ---------- Previous post was at 12:22 AM ----------

Originally Posted by DrHappyAngry

Well if you're planning on booting from that other drive you'll need to edit the fstab in the new install, as well as install the bootloader to that drive. I think it's just "grub-instal /dev/sdX" where sdX is the drive you want to install to. To find the UUID of the new partitions on the new drive run "blkid" and change the uuid for / to the one you got from blkid.

the "new" drive already has grub loaded, like I said both disks boot, I just wanted to take a fully configured system disk and copy it to the new ssd drive.

[jpollard]

Originally Posted by toddbailey

I've been googling the topic and can't I just use a cp -pr /source /destination or am I missing something?

I would say use "cp --preserve=all -Pr".

Using just -p only saves the mode, ownership, and timestamps. The files also have a security label that needs to be saved. Of course, you could run a "restorecon /" after you boot the copied system (or add a "touch .autorelable" in the new root filesystem), but saving the labels is faster.

[toddbailey]

problem solved:

I failed to notice there is a root uuid entry in grub.conf.
a simple edit and a reboot and now the machine boots with it's new drive.


next project to apply SSD settings and move r/w folders to the secondary drive.

for those who want to try this here are the steps in brief I used.

setup drive to clone to
boot using a usb key
creat folder in mnt ie src and dest
mount source and dest devices
run rsync
get device id's
edit fstab and grub and update the uuid entries.

pretty simple after a few failed attemps....