Re: copying a disk image to restore on linux

[Kevin Currie <kcurrie () cisco com>]

        If you are going to use dd to backup a partition, you might want
to zero out all of the unused space first, so it will compress better.
dd if=/dev/zero of=/bigZEROfile ; rm /bigZEROfile
The dd will fill the disk with a large file full of zeros, then exit when
the disk is full, then delete the file.  Now all "free" space on the disk
should have highly compressable zeros in it.




stefmit wrote:
> Are you saying that:
>
> # df -h ==> used MB or GB
>
> then:
>
> # dd if=/dev/hda1 bs=1M count=<used MB or GB> | gzip > hda1-image.gz
>
> then, on the new drive:
>
> # zcat hda1-image.gz | dd of=/dev/hda1 >& /dev/null
>
> won't cut it for you?!?
>
> On Tuesday 24 December 2002 04:12 am, phani () myrealbox com wrote:
>
> > hi all,
> >   I would like to know if there are any utilities on linux (preferably
> > freeware) which can create a complete image of the hard-drive. I know dd
> > exists, but that would create the image of the entire drive. If the drive
> > was (say) 40 GB and the free space is 20 GB then that would be a waste of
> > space. Is there a tool which would let me create the image of the used
> > space on the drive ?
> >
> > thank you
> > gangadhar

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