freebsd ISO is bloated

kobasay · Mar 1, 2025

hello, sorry I'm new here, I'm just trying to use freebsd, currently I'm trying to make an ISO using mkisoimage.sh with chroot base freebsd but the problem here is that the freebsd ISO that I made using mkisoimage.sh has bloated to 4GB+ even though the chroot only has around 2GB when I check it using 'du -sh'

T-Daemon · Mar 2, 2025

kobasay said:
I made using mkisoimage.sh has bloated to 4GB+ even though the chroot only has around 2GB when I check it using 'du -sh'

What do you get with du -shA (-sA) on the chroot base?

du(1)

Code:

     -A      Display the apparent size instead of the disk usage.  This can be
             helpful when operating on compressed volumes or sparse files.

When chroot base is on ZFS with compression property "on", the saved iso on ZFS without compression or UFS (or other FS), then this can explain the size discrepancy.

For example Root-on-ZFS with zfs property "compress=lz4":

Code:

 # du -s /images/14.2-RELEASE 
556986  /images/14.2-RELEASE

 # du -sh /images/14.2-RELEASE
544M     /images/14.2-RELEASE


 # du -sA /images/14.2-RELEASE
1000258     /images/14.2-RELEASE

 # du -shA /images/14.2-RELEASE
977M     /images/14.2-RELEASE

kobasay · Mar 2, 2025

T-Daemon said:
What do you get with du -shA (-sA) on the chroot base?

du(1)

Code:

-A Display the apparent size instead of the disk usage. This can be helpful when operating on compressed volumes or sparse files.

When chroot base is on ZFS with compression property "on", the saved iso on ZFS without compression or UFS (or other FS), then this can explain the size discrepancy.

For example Root-on-ZFS with zfs property "compress=lz4":

Code:

# du -s /images/14.2-RELEASE 556986 /images/14.2-RELEASE # du -sh /images/14.2-RELEASE 544M /images/14.2-RELEASE # du -sA /images/14.2-RELEASE 1000258 /images/14.2-RELEASE # du -shA /images/14.2-RELEASE 977M /images/14.2-RELEASE

Hey! Thank You! this is a game changer, yeah! The output from the 'du -shA' command in chroot has the same size as the ISO size (4GB)! okay! I'll find out more myself! thanks again!