Using dump/restore to combine partitions?

[Ronald F. Guilmette]

I have a bootable FreeBSD system that was partitioned in a way that I dislike,
and that I would like to now change. The current system contains the following
partitions, which I would like to copy to a fresh new drive while consolidating
all of these partitions into a new _single_ partition on the new drive. (The
new drive will end up being my new bootable drive.):

Filesystem 1M-blocks Used Avail Capacity Mounted on
/dev/ada0p2 991 618 293 68% /
devfs 0 0 0 100% /dev
/dev/ada0p4 2973 1357 1378 50% /var
/dev/ada0p5 1983 16 1808 1% /var/ftp
/dev/ada0p6 991 14 897 2% /tmp
/dev/ada0p7 15853 12749 1835 87% /usr
/dev/ada0p8 31726 27545 1642 94% /home
procfs 0 0 0 100% /proc

My question is: How do I accomplish this using dump/restore?

My current plan is to boot the system in question from a removable device
that will itself contain a full FreeBSD 15.1-STABLE system, mount the target
filesystem, perform all of the necessary dump and restore operations,
power-off, remove the removable drive, remove the old boot drive and then
boot from the new drive.

I need to know the exact set of commands necessary to accomplish all this.

Assuming that the new (single) bootable partition on the new drive will be
pre-formatted (UFS) and mounted as /mnt and that the source partitions
described above will end up having all of the same /dev names as listed
above, but with "ada0" changed to "ada1", then will the following set of
commands accomplish my goal?

cd /mnt
dump -0f - /dev/ada1p2 | restore -rf -
cd /mnt/var
dump -0f - /dev/ada1p4 | restore -rf -
cd /mnt/var/ftp
dump -0f - /dev/ada1p5 | restore -rf -
cd /mnt/tmp
dump -0f - /dev/ada1p6 | restore -rf -
cd /mnt/usr
dump -0f - /dev/ada1p7 | restore -rf -
cd /mnt/home
dump -0f - /dev/ada1p8 | restore -rf -

Thanks in advance for any & all guidance.

[Dan Mahoney (Ports)]

In a talk at BSDCan I posted a slide that I titled "here goes nothing" where during a pandemic where smart hands was literally not allowed to come to the office, on a faraway system running Critical Things, that I had no out of band access to, I would copy mfsbsd over /boot, reboot and hope for the best, which would give me a memory-resident booted OS that would suspend me, mission-impossible-style, over the disk so I could reformat and reinstall, because a prior coworker had made / and /var too small to take a freebsd-update to a modern OS.

I mean, maybe, but....first off, you're going to be copying /usr over, which contains /usr/lib and /usr/bin and also /usr/local (so thus, all your installed binaries) with whatever shared libs (both base and from ports) that you had at the time. This feels like a great way to induce pain. Just reinstall your packages clean. `pkg leaf` should show you the minimal install requirements. From there, it *should* just be choice bits in /etc, most of /usr/local/etc, /home (wherever that is) and maybe /var (but again, you don't want to stomp your new pkg database). What's in /tmp that you really care about after a reboot?

And second, dump is an interesting solution for streaming a partition/mountpoint to either a tape device, or over a pipe, but it's very block-level, which you don't really need. Yes, there are some filesystem flags like noschg and stuff that a plain-vanilla `cp -pR` won't capture, but tar should absolutely suffice here. Or Rsync.

-Dan

[Paul Vixie]

<<because a prior coworker had made / and /var too small to take a freebsd-update to a modern OS.>>

Sorry about that!

Paul Vixie

May 21, 2026 18:20:50 Dan Mahoney (Ports) <fre...@gushi.org>:

[Dag-Erling Smørgrav]

"Ronald F. Guilmette" <r...@tristatelogic.com> writes:
> My question is: How do I accomplish this using dump/restore?

The restore utility doesn't care what it restores onto and will happily
cross filesystem boundaries while extracting. Just make sure the new
filesystems are all mounted in the correct locations (relative to each
other) and with the correct permissions before restoring.

DES
--
Dag-Erling Smørgrav - d...@FreeBSD.org