On Tuesday 24 of August 2010 21:35:20 Flavio Costa wrote:

On Tue, Aug 24, 2010 at 4:14 PM, Marek Otahal wrote:

...

Hi all,

I use dd command to make an image of entire /dev/sda (160GB) and back up it as netobook.hdd to an external storage. The disk contains both encrypted(dmcrypt/luks) and normal linux/win partitions.

My question is, if my netbook died and I needed to recover from backup, can I just dd-copy the image to a new larger disk? Does it matter?

1/ it will do, but the size will remain 160gb ..is ok. 2/ will do & possibility to resize partitions later ..even better! :)

I've searched the net, but I'd like someone to confirm it 100% works (just dd and reboot).

Thanks in advance, Marek

--

Marek Otahal :o)

The destination drive must have a greater or equal capacity, otherwise you will probably lose data / get a corrupt filesystem. After the dd finishes you can use any program that messes with partitions to resize it, in case the disk is bigger.

I can confirm that this simply works, no trick needed. I've done it dozens of times.

Thank you Flávio, that's what I wanted to be reassured about. -- Marek Otahal :o)

On Tuesday 24 of August 2010 23:03:23 Mauro Santos wrote:

On 08/24/2010 08:14 PM, Marek Otahal wrote:

...

Hi all,

I use dd command to make an image of entire /dev/sda (160GB) and back up it as netobook.hdd to an external storage. The disk contains both encrypted(dmcrypt/luks) and normal linux/win partitions.

My question is, if my netbook died and I needed to recover from backup, can I just dd-copy the image to a new larger disk? Does it matter?

1/ it will do, but the size will remain 160gb ..is ok. 2/ will do & possibility to resize partitions later ..even better! :)

I've searched the net, but I'd like someone to confirm it 100% works (just dd and reboot).

Thanks in advance, Marek

Most probably you don't even need to copy the image back to a disk to get the files you need. I don't know about the encrypted(dmcrypt/luks) partitions but the "normal" linux/win partitions can be accessed directly from the image.

Is that so? I like the restore to a functional computer ability, so copying seems useful. But I was wondering how to mount a specific partition from an image? (i make the image of whole /dev/sda, so sda1,2,..are hidden inside) greetings, Marek -- Marek Otahal :o)

On 24 August 2010 16:02, Mauro Santos wrote:

On 08/24/2010 10:20 PM, Marek Otahal wrote:

...

On Tuesday 24 of August 2010 23:03:23 Mauro Santos wrote:

...

On 08/24/2010 08:14 PM, Marek Otahal wrote:

...

Hi all,

I use dd command to make an image of entire /dev/sda (160GB) and back up it as netobook.hdd to an external storage. The disk contains both encrypted(dmcrypt/luks) and normal linux/win partitions.

My question is, if my netbook died and I needed to recover from backup, can I just dd-copy the image to a new larger disk? Does it matter?

1/ it will do, but the size will remain 160gb ..is ok. 2/ will do & possibility to resize partitions later ..even better! :)

I've searched the net, but I'd like someone to confirm it 100% works (just dd and reboot).

Thanks in advance, Marek

Most probably you don't even need to copy the image back to a disk to get the files you need. I don't know about the encrypted(dmcrypt/luks) partitions but the "normal" linux/win partitions can be accessed directly from the image.

Is that so? I like the restore to a functional computer ability, so copying seems useful. But I was wondering how to mount a specific partition from an image? (i make the image of whole /dev/sda, so sda1,2,..are hidden inside)

greetings, Marek

Usually I do it like this: - mount (?) the image to a loop device losetup /dev/loop0 /path/to/image/file

- get the start of partitions parted /dev/loop0 unit B print

take notice of the starting bytes for the partition you want to mount mount /dev/loop0 mnt_point -o offset=start_bytes

and thats it, you should be able to access at least the "normal" partitions (read and write). I have never tried with encrypted partitions, I guess you would have to pass some extra options to mount.

To unmount everything cleanly do: umount mnt_point losetup -d /dev/loop0

-- Mauro Santos

But why? The loop module supports partitions now, just modprobe it with max_part=10 or something. The partitions will be /dev/loop0p[1234...]. -- Tavian Barnes

On Wednesday 25 of August 2010 01:02:21 Mauro Santos wrote:

On 08/24/2010 11:44 PM, Tavian Barnes wrote:

...

On 24 August 2010 16:02, Mauro Santos wrote:

...

On 08/24/2010 10:20 PM, Marek Otahal wrote:

...

On Tuesday 24 of August 2010 23:03:23 Mauro Santos wrote:

...

On 08/24/2010 08:14 PM, Marek Otahal wrote:

...

Hi all,

I use dd command to make an image of entire /dev/sda (160GB) and back up it as netobook.hdd to an external storage. The disk contains both encrypted(dmcrypt/luks) and normal linux/win partitions.

My question is, if my netbook died and I needed to recover from backup, can I just dd-copy the image to a new larger disk? Does it matter?

1/ it will do, but the size will remain 160gb ..is ok. 2/ will do & possibility to resize partitions later ..even better! :)

I've searched the net, but I'd like someone to confirm it 100% works (just dd and reboot).

Thanks in advance, Marek

Most probably you don't even need to copy the image back to a disk to get the files you need. I don't know about the encrypted(dmcrypt/luks) partitions but the "normal" linux/win partitions can be accessed directly from the image.

Is that so? I like the restore to a functional computer ability, so copying seems useful. But I was wondering how to mount a specific partition from an image? (i make the image of whole /dev/sda, so sda1,2,..are hidden inside)

greetings, Marek

Usually I do it like this: - mount (?) the image to a loop device losetup /dev/loop0 /path/to/image/file

- get the start of partitions parted /dev/loop0 unit B print

take notice of the starting bytes for the partition you want to mount mount /dev/loop0 mnt_point -o offset=start_bytes

and thats it, you should be able to access at least the "normal" partitions (read and write). I have never tried with encrypted partitions, I guess you would have to pass some extra options to mount.

To unmount everything cleanly do: umount mnt_point losetup -d /dev/loop0

-- Mauro Santos

But why? The loop module supports partitions now, just modprobe it with max_part=10 or something. The partitions will be /dev/loop0p[1234...].

Nice tip. I've been using this method for quite a while so either it wasn't available when I started using it or I missed the fact that the module option is needed for this to work.

thank you very much both of you! I'll use the modprobe w/ max_part argument solution. -- Marek Otahal :o)