Restoring dd image issues

[RobertCo]

Hello,
First I would like to thank you all for the great wealth of information that I have found here and used in my use of NIX servers.

I have a server which I created an image of by using the following commands:
1.

dd if=/dev/zero of=/tmp/zero bs=64k

zero out free space
2.

dd if=/dev/zero of=/home/zero bs=64k

because /home is largest partition on server wanted to make sure I compressed well there as well.
3.

dd if=/dev/sda bs64k | gzip -9 >/remotemnt/testimage/test1.img.gz

Create the image compressed.
The size of the image compressed is 606250630 Aug 28 17:48 test1.img.gz Fairly large since the drives are 250GB

So not to endure network slowness by restoring the image via network I have copied the compressed image to a CD as well as a USB Flashdrive.
I am attempting to use the FlashDrive to restore the image.

---------------------------------
now for the restore process.

1. Boot knoppix Live cd with bot option knoppix 2 text mode only

2. I make sure that the disk is not being used for anything including swap

swapon -s

swapoff /dev/sdaX

umount /dev/sdaX

3.

mkdir /mnt/usb

4.

mount /dev/sdbX /mnt/usb

Mounts USB so I can read it to sbdX ususally /dev/sbd1 if I boot initially and then plug usb in.

5.

gzip -d /mnt/usb/test1.img.gz |dd of=/dev/sda bs=64k

This is failing due to not enough space on device.
I am thinking this is because gzip wants to uncompress the image on the usb device which only has 1 GB of space of which is already more then 58% used due to the image file being compressed there.

Is there a way I can uncompress the image and not have it write it to the usb device or the disk where it is going to be restored to ?
possibly a loop device ?
If so can you please show me how ?
Thank you very much as I am a Noob to SysAdmin responsibilities

[RobertCo]

After further review I am trying to run the following which I believe is working

zcat /mnt/usb/test1.img.gz >/dev/sda

I will update this thread once I complete my test to let you know if it all works smooth.

[RobertCo]

this process worked great. Now I just have to duplicate the process and make sure I can use the knoppix Live CD to mount a network drive (which I am sure it will be able to do)

[malaire]

5.

gzip -d /mnt/usb/test1.img.gz |dd of=/dev/sda bs=64k

This is failing due to not enough space on device.
I am thinking this is because gzip wants to uncompress the image on the usb device which only has 1 GB of space of which is already more then 58% used due to the image file being compressed there.

You should use -c switch for gzip which will write the output to stdout, i.e.

gzip -cd /mnt/usb/test1.img.gz |dd of=/dev/sda bs=64k