FreeBSD and DragonFlyBSD on same harddisk

H

hwagemann

Hello,

I want to compare FreeBSD and DragonFlyBSD. For installation of both systems I want to use my 128 GB ssd with GPT, starting with FreeBSD and then adding DragonFlyBSD. But how to prepare this disk? Would this work?
Code: 
ada1p1 freebsd-boot 512 K
ada1p2 freebsd 50 G
ada1p3 df-boot 512 M
ada1p4 df 50 G
ada1p5 swap for both systems 8 G

I need further help, thanks in advance.

Kind regards,
Holger
 
hwagemann said:
Hello,
I want to compare FreeBSD and DragonFlyBSD. For installation of both systems I want to use my 128 GB ssd with GPT, starting with FreeBSD and then adding DragonFlyBSD. But how to prepare this disk?
Click to expand...
I have never dual booted anything in my life so I would not know but reading the documentation and learning about how the boot process works on FreeBSD

https://www.freebsd.org/doc/handbook/boot.html

and DF

https://www.dragonflybsd.org/docs/newhandbook/Booting/

would be the start. Some basic understanding of MBR v/s GPT and BIOS v/s UEFI is must.

https://wiki.manjaro.org/index.php?title=Some_basics_of_MBR_v/s_GPT_and_BIOS_v/s_UEFI

A quick search of DF users mailing list

http://marc.info/?l=dragonfly-users&r=1&w=2

reveals that many people do dual boot DF with other OSs.
 
Hello Oko,

thanks for your hints. In my case booting procedure is managed by grub2 of my arch installation, I'll add a further entry for DragonFlyBSD.

My question more refers to the partitions. Could I use a third partition of a harddisk as bsd-boot? In handbook I read about a max size of 512 K for freebsd-boot but no further restrictions, so I guess, it doesn't need first partition of a harddisk. I further guess, that swap can be shared.

Kind regards,
Holger
 
hwagemann said:
I want to compare FreeBSD and DragonFlyBSD. For installation of both systems I want to use my 128 GB ssd ....
I need further help, thanks in advance.
Click to expand...

I had a similar need to be able to boot either FreeBSD 10.2 or 11-CURRENT or NextBSD or ... other, but my system was already loaded with two SSDs (one with FreeBSD and one with Gentoo/Funtoo) and a zfs two-disk mirror (Western Digital Red NAS drives). So I made the boot drive physically swapable by puttting a hot swap drive bay in one of the 5.25-inch bays. Of course this solution assumes a standard PC box, not a notebook computer. Now I can completely swap the boot drive and allow each OS to have its own drive and its own boot loader and I can play around safely with alternate systems.

I don't know if such a solution is even possible for your hardware but ... it works for me. :)
 
garry said:
I had a similar need to be able to boot either FreeBSD 10.2 or 11-CURRENT or NextBSD or ... other, but my system was already loaded with two SSDs (one with FreeBSD and one with Gentoo/Funtoo) and a zfs two-disk mirror (Western Digital Red NAS drives). So I made the boot drive physically swapable by puttting a hot swap drive bay in one of the 5.25-inch bays. Of course this solution assumes a standard PC box, not a notebook computer. Now I can completely swap the boot drive and allow each OS to have its own drive and its own boot loader and I can play around safely with alternate systems.

I don't know if such a solution is even possible for your hardware but ... it works for me. :)
Click to expand...
Hey garry,

thanks for your hints. The harddrive constallation on my computer is following:
Code: 
/dev/sda with GPT 256 GB
/dev/sda1    Arch Linux
/dev/sda2    Debian GNU/Linux
/dev/sda3    siduction
/dev/sda4    linux-swap
/dev/sdax    place for further Linux Distributions
/dev/sda128 bios_grub

/dev/ada1  with GPT 128 GB
/dev/ada1p1  freebsd-boot
/dev/ada1p2  freebsd
/dev/ada1p3  freebsd-swap

/dev/sdc with GPT 1 TB
/dev/sdc1 ext2 shared data for Linux and FreeBSD

FreeBSD start is managed by grub2 of Arch Linux. I want to prepair /dev/ada1 for a new installation of FreeBSD and want to add DragonFlyBSD. I don't want to modify stuff on first and third harddisk, apart from a further entry in /boot/grub.cfg for my new DragonFlyBSD installation.

I'll test following:
Code: 
ada1p1 freebsd-boot 512 K
ada1p2 freebsd 50 G
ada1p3 df-boot 512 M
ada1p4 df 50 G
ada1p5 swap for both systems 8 G

I've made a short test with df on my notebook, comparing with partitioning of FreeBSD there I've seen another kind of partitioning:
Code: 
ada0p1
ada0p1a
ada0p1b
ada0p1c

Hmm, could somebody explain this?

Kind regards,
Holger
 
Dear hwagemann,
when I have started using FreeBSD I have had a single disk with 1x Linux and grub and 2x FreeBSD Installations using the MBR partitioning scheme.
The notation as ada0p1a seems to be as a FreeBSD partition in the slice ada0p1. Unfortunately the FreeBSD slice is named as partition in other context as under Windows or Linux. This can be somehow confusing.
Please see https://www.freebsd.org/doc/en_US.I...disk-organization.html#basics-disk-slice-part for details.
 
Short version: use GPT, avoid MBR.

Longer version:
MBR is the old partitioning method, allowing only four "slices" on a drive (s is for "slice" on FreeBSD). FreeBSD's even older and superior disklabel partitioning allowed many more partitions on a disk, each using a letter, and so the idea was hit upon to put FreeBSD partitions inside an MBR slice, providing the worst of both worlds: https://www.freebsd.org/doc/en_US.I...k-organization.html#basics-concept-disk-model.

GPT allows many partitions on a drive, up to 128 by default. On FreeBSD, these partitions are represented by a p. Because there is no need to put FreeBSD partitions inside a single GPT partition, it simplifies things. It is possible, but I have not seen anyone do it yet. There is no point.

I do not know what DragonFly does for device names. On FreeBSD, ada0p1a would be from that pointless combination of GPT and FreeBSD disklabel.
 
BSD partitions now just use letter names. Maybe it's bsd64 partitions, since it's hard to find documentation on it. I used it and my drives are numbered:
Code: 
ada0a
ada0b
ada0d
It skips ada0c, because it's reserved for some reason. It allows more real partitions than 4, but it still has a limit.
 
bsdlabel(8) partitions have always used letters. If there is no p or s before them, it means the disk only has BSDlabel partitioning. That is unknown outside of the BSD world, and called "dangerously dedicated".

The c partition represents the whole disk. The only reason to use BSDlabel partitioning is when GPT cannot be used for some reason.
 
Hello,

thanks for your explanation.

Just as reminder: I've not forgotten my promise to write something about installing FreeBSD as desktop system for beginners. But I need some more time for it.

Kind regards,
Holger
 
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