Recreating the FreeBSD Installation Disks

Rick Miller vmiller at
Fri Aug 29 14:42:20 UTC 2014

Hi, I realize I'm late in the game...inline...

On Wed, Aug 27, 2014 at 10:25 AM, Martin G. McCormick <
martin at> wrote:

>         I have been asking lots of questions recently about
> whether the procedure for building a custom FreeBSD installation
> CD has changed and it apparently has not but the problem I am
> having is not hard to define.
> The original image downloaded from is:
> FreeBSD-9.1-RELEASE-amd64-disc1.iso and it is
> 718862336 bytes large.
> I mounted it on a FreeBSD9 system as follows:
> ##Set up memory disk.
> # mdconfig -f FreeBSD-9.1-RELEASE-amd64-disc1.iso -u 1
> ##Mount it.
> #mount -t cd9660 /dev/md1 /mnt2
>         Everything looks normal if you ls /mnt2.
> If one was to use mkisofs with /mnt2 as the top of the tree, a
> new iso image file should appear somewhere that is about the
> same size as the starting ISO file. As a test to see if this
> happens, I did the following:
> #   mkisofs -J -R -V customBSD -no-emul-boot -b boot/cdboot -iso-level 3
> -o \
> #/home/martin/tmp/serialcd64.iso .
> #ls -l /home/martin/serialcd64.iso
> -rw-r--r--  1 root  martin  833892352 Aug 26 10:48 serialcd64.iso
> Man! I sure wish my pay check could do that after a week of
> living.
>         I know that hard links will make tar and rsync produce
> larger outputs if not called correctly. My understanding is that
> hard links are multiple sets of inode numbers pointing to the
> same files so they are hard to mechanically distinguish from
> actual disk space being occupied by the same data in more than
> one spot.
>         When one needs to make a custom CD, the extremely
> difficult part is recreating the steps that were used to
> originally build the image.
>         An amusing side note; I used rsync to create a writable
> copy of the tree as follows:
> #cd ./treetop
> #sudo rsync -a /mnt2/ ./
>         A few seconds later, I had something that built without
> a single complaint so I made an image out of treetop and got:
> #ls -l custom*
> -rw-r--r--  1 martin  martin  455213056 Aug 26 11:42 custom.iso
>         That was the exact same file tree that insists on being
> 120 MB too large if you try to make a straight ISO image from
> the mounted file system of the original image which is about 300
> MB larger than this one.
>         That has been pretty much the story of the last few days
> and I am running out of things to try. The process for building
> the FreeBSD installation CD is clever since it manages to cram
> so much in to the limited space without compressing the entire
> image. So far, orthogonalness has escaped me at every turn.

You have already been back and forth working on this via the list and I
have nothing very meaningful to contribute except that I encountered a
problem using the 10.0-RELEASE bootonly ISO on a few bare metal chassis'
(though 8.0-RELEASE bootonly ISO has worked nearly 4 years installing 8.x).
 A solution to the problem, described in PR190939[1], has not been
determined.  However, switching from the bootonly ISO to mfsBSD[2] has,
thus far, proven successful in performing fully automated, non-interactive

mfsBSD provides several advantages over the ISO including, but not limited
to, being mounted rw (as opposed to ro in the ISO) and it's much smaller
footprint (~40MB image vs 200MB+ ISO).  Perhaps mfsBSD can be considered as
an alternate installation media?


Take care
Rick Miller

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