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For the complete documentation index, see llms.txt. This page is also available as Markdown.

16.4 Installing FreeBSD on KVM, QEMU, and Other Platforms (Legacy Boot/MBR)

On KVM/QEMU and other hardware-assisted virtualization platforms, installing FreeBSD via traditional BIOS + MBR is suitable for cloud service environments that do not directly provide FreeBSD images. The MEMDISK boot method described in this section does not support UEFI booting, nor is it applicable to containerized platforms such as OpenVZ and LXC.

Note

Because containerization technology is inherently not a complete virtualization solution — the host and guest share the same kernel — this method does not support containerized technologies such as OpenVZ and LXC. The kernel is already Linux, and FreeBSD cannot be run.

The MEMDISK boot method described in this section does not support UEFI boot mode (BIOS + GPT partition table is also not supported); it only supports the traditional BIOS + MBR boot method. Please ensure your environment meets the requirements. If UEFI booting is needed, consider using mfsBSD's UEFI support or other boot solutions.

Warning

Please be aware of data security. The following tutorial carries certain risks and requires the operator to have the corresponding operational capabilities and system administration knowledge.

Overview

This section introduces the method for installing FreeBSD on KVM, QEMU, and other platforms. Most service providers using KVM and QEMU virtualization architectures do not directly provide FreeBSD system support, requiring manual installation through special methods.

Some service providers offer FreeBSD system images on certain machine types, but support is not yet complete — for example, the default images do not have BBR enabled, and some machine types do not provide FreeBSD support at all.

This method does not require using mfsLinux as installation media, nor does it require installation via the dd command.

mfsBSD is a FreeBSD system that is entirely loaded into memory, similar to Windows PE (Preinstallation Environment).

This section uses GRUB2 with the MEMDISK module to load mfsBSD into memory and boot from it, then installs FreeBSD through the bsdinstall command in mfsBSD.

Obtaining Existing Network Configuration

Some servers may not have DHCP service enabled, requiring manual IP specification; this is more common with smaller service providers.

Before installation, please confirm the IP address and subnet mask in the original Linux system. You can use the commands ip addr and ip route show to view gateway information.

Preparing mfsBSD

Download mfsBSD. You can download it to a local computer and then upload it to the server via SCP, SFTP, or WinSCP; you can also download it directly on the server using the command line.

Note

Because mfsBSD's download site does not support IPv6 networks, servers that only support IPv6 cannot download via the command line.

Regarding this issue, the author has been contacted via email, but no reply has been received as of press time.

Memory ≤ 512 MB

Download the mfsBSD Mini 14.2-RELEASE ISO image:

Checksum (the official website link is incorrect; feedback has been submitted but no reply received): checksums

Note

Machines with 4 GB of memory or less are not recommended to use the ZFS file system.

mfsBSD Mini uses Dropbear SSH instead of OpenSSH, but still includes the zfs kernel module, supporting the ZFS file system.

Memory > 512 MB

Download the mfsBSD 14.2-RELEASE AMD64 ISO image:

Checksum: checksums

Preparing mfsBSD.iso

Rename the downloaded mfsBSD to mfsbsd.iso and place it in the /boot directory (placing it in other directories may result in hard disk partitions not being recognized due to LVM).

Obtaining memdisk

memdisk is a tool provided by syslinux for loading ISO images into memory.

Warning

The memdisk.mod module included with GRUB2 is not the MEMDISK required here.

memdisk must be obtained from syslinux installed via the package manager.

Installing syslinux

The command to install syslinux varies across different Linux distributions.

  • Debian/Ubuntu

  • Rocky Linux

Extracting memdisk

Extract the memdisk file from the installed syslinux package to /boot:

  • Debian/Ubuntu

  • Rocky Linux

Unhiding the GRUB Menu

Disable the GRUB2 menu auto-hide setting:

Booting mfsBSD

After restarting and entering the GRUB menu, press c to enter command line mode:

Press C on this interface
GRUB command line interface

Tip

If you encounter issues, try switching to the serial console (console=comconsole) or check the image integrity.

In Proxmox, you can directly click the xterm.js button on the interface to enter the serial console for troubleshooting.

Select the xterm.js button
Enter xterm.js for troubleshooting

Configuring the Network for mfsBSD

The default root password for mfsBSD is mfsroot. You can connect using an SSH tool and then install.

Tip

If the platform supports DHCP for automatic network configuration, you can skip this section.

After rebooting into mfsBSD, configure the network.

Using interface vtnet0 as an example, configure IPv4:

Warning

Please replace the examples below with actual IP addresses and routing information.

Check the network configuration:

Starting the Installation

Use kldload zfs to load the ZFS module, then run bsdinstall.

This step can follow the installation method described in other chapters.

Troubleshooting and Unfinished Business

How to Install with a GPT Partition Table?

Refer to the following resources:

This issue requires further research.

VMware and VirtualBox Cannot Be Installed Using This Method

VirtualBox users can try selecting "KVM" as the virtualization engine and then booting again, but this may vary by environment (the test environment failed to boot successfully).

VirtualBox selecting virtualization

Approaches to Try

The following approaches have not been verified and are provided for readers to try.

Can enter BootLoader, but boot fails

Idea: You can use the ? command on this interface to view disk information, which may allow continuing the boot process.

  • Use mfsLinux to dd mfsBSD

Cannot enter BootLoader

This issue remains to be verified.

References

  • mfsBSD. mfsBSD — minimalistic FreeBSD distribution[EB/OL]. [2026-04-17]. https://mfsbsd.vx.sk/. mfsBSD project homepage, providing FreeBSD system images that are entirely loaded into memory.

  • syslinux Wiki. MEMDISK[EB/OL]. [2026-04-17]. https://wiki.syslinux.org/wiki/index.php?title=MEMDISK. MEMDISK module documentation, used for loading ISO images into memory as virtual disks.

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