image creating (simple backup)

JoeB barbish at
Mon Apr 14 08:49:24 PDT 2003

>From the archives

The question of using the Norton Ghost program to make an single
image file of an hard drives partition containing FBSD has been
many times on this list. UP until now the answer has all ways been
the benefits of using Ghost on a MS/win partition can not be
when used on a FBSD slice because the ghost created image file
contains all the unused space as well as the used space.

Jacob S. Barrett had the idea of zeroing out the unused space before
running ghost so ghost will compress all the zero filled space
resulting in an image file size and elapse run time comparable to
you would achieve on a MS/win partition. This is a great work

Before running the Ghost program from native booted ms/dos you have
to run this command on FBSD before shutting FBSD down.

dd if=/dev/zero of=filler bs=1m ; rm filler

Below is the original thread

> -----Original Message-----
> From: owner-freebsd-questions at FreeBSD.ORG
> [mailto:owner-freebsd-questions at FreeBSD.ORG]On Behalf Of Dan
> Sent: Friday, October 04, 2002 10:33 AM
> To: Jacob S. Barrett
> Cc: freebsd-questions at FreeBSD.ORG
> Subject: Re: Block Zeroing Tool
> In the last episode (Oct 04), Jacob S. Barrett said:
>>Is there a tool for FreeBSD that zeros the unallocated blocks on a
>>The company I work for has an image on demand system for our lab
>>machines.  This system relies on ghost which only supports file by
>>file imaging on certain file systems.  I want to take disk images
>>certain FreeBSD installations.  Ghost will only take sector by
>>images of FreeBSD partitions.  Since it is doing this it stores
>>the "junk" unused blocks as well.  This makes for a very large
>>even with high compression.  If I can zero out the unused blocks
>>before taking the image with high compression the image size
>>be much smaller.
>>So, is there utility to zero out those blocks?  Does this make
>>Is there a better way to take images of FreeBSD machines?

> dd if=/dev/zero of=filler bs=1m ; rm filler
> I also have tried to use ghost to make image backups of FBSD,
> but the image is the same size as the FBSD slice.
> Have you tested the solution posted above to zero out the unused
> disk space in the FBSD slice so ghost will only image bkup real
> Did it work like you hoped?

Yes I have tested it,  and it works great.  Be sure to turn
on to high to get the best results.  Here is what I saw after
the unallocated blocks using the dd command.

FreeBSD partition size: 11G
Allocated space: 6G
Ghost image size: 3.4G

Before zeroing out the images on this box were between 8-9G.
to say our IT guy is much happier that my box isn't chewing up 9G
image on the system anymore.  And I am happy that imaging this
only takes an hour now rather than 4.


Jacob S. Barrett
jbarrett at

-----Original Message-----
From: owner-freebsd-questions at
[mailto:owner-freebsd-questions at]On Behalf Of Hilmi
Sent: Monday, April 14, 2003 11:35 AM
To: freebsd-questions at FreeBSD.ORG
Subject: image creating (simple backup)

Dear All,

I would like to make a image from one of my HDD. The FreeBSD box
now with FreeBSD 4.7. Is a possible ot create image via Symantec
or PQ Drive Image? Or have other way for image creating?

Best regards,


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