# FreeBSD 10.3 zfs installation on existing Windows10?



## reo7189 (May 30, 2016)

I'm about to install a FreeBSD 10.3 with ZFS filesystem on existing Windows 10, could anybody here help me how to go through the FreeBSD installation and finally with dual boot?


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## mseqs (May 30, 2016)

ZFS can only be installed with 'entire disk mode', so you need to format your entire hard drive to use *only* ZFS


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## SirDice (May 31, 2016)

mseqs said:


> ZFS can only be installed with 'entire disk mode', so you need to format your entire hard drive to use *only* ZFS


No, not exactly. If you mean the installer can only do a 'whole' disk then you are correct. But there's nothing stopping you from doing a custom install. It is very much possible to install both Windows and a ZFS FreeBSD on the same disk. I've done so in the past. 

But it's tricky to do and I don't have the system any more to check. One of the problems I faced was selecting which system to boot. Back then FreeBSD wasn't able to UEFI boot. I more or less 'solved' it by UEFI booting Windows and selecting the 'traditional' boot to boot FreeBSD. Things might be a bit better now FreeBSD can also UEFI boot.

One thing that was absolutely essential was getting Windows to install on a GPT partitioned drive. Which can only be done if you boot the Windows installer in UEFI mode.


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## kpa (May 31, 2016)

You can install 64-bit version of Windows 7 on a GPT partioned disk without UEFI.


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## SirDice (May 31, 2016)

kpa said:


> You can install 64-bit version of Windows 7 on a GPT partioned disk without UEFI.


When I booted the Windows installer 'traditionally' I wasn't able to create GPT partitions, apparently it was only possible to create one when I UEFI booted the installer. Mind you this was on a completely empty disk, I don't now what happens if the GPT partitioning is already there.


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## ANOKNUSA (May 31, 2016)

While it's possible to install FreeBSD alongside Windows on one disk, and (maybe) possible to do so with ZFS, it isn't easy. I'd consider it a process for advanced users only. There are certain things you'd want to be familiar with:

The FreeBSD boot process. There are two bootloaders for legacy BIOS motherboards, and one for UEFI motherboards. Each one requires a different partitioning scheme and filesystem layout.

As SirDice pointed out, which bootloader you choose at least partly depends on how you installed Windows.

How to use FreeBSD tools to manage disks, and configure an installed system. _All system maintenance_ in FreeBSD is done using a command line interface and a text editor.

ZFS itself. Dual-booting could only be set up if you manually created a ZFS pool and datasets during installation, so without understanding how ZFS works and how to manage it you can't really do this.
Some of this information can be found in the _FreeBSD Handbook_ There are other things to take into account as well, but the gist of it is that as with the Windows installer, the FreeBSD installation process and bootloaders are really designed to install FreeBSD to its own dedicated disk. I would recommend looking up some guides on installing FreeBSD root-on-zfs (there are plenty) and dual-booting, and trying things out in a virtual machine first.


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## mseqs (May 31, 2016)

SirDice said:


> No, not exactly. If you mean the installer can only do a 'whole' disk then you are correct. But there's nothing stopping you from doing a custom install. It is very much possible to install both Windows and a ZFS FreeBSD on the same disk. I've done so in the past.


I didn't know that. I tried using ZFS alongside other file systems before but with no success, and I did not found enough information on the internet, so I gave up. Thanks for the tip, maybe I try that in the future


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