Ideal dual boot partition scheme

BullettuPaandi said:

Aside from the space required for the OS, I want the rest to be accessible from both.

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Other than the OS partition of Ubuntu keep all other partitions NTFS. Linux can read and write NTFS partitions just fine

Keeping Windows and Linux on different storage devices is better option I think.
Also, keep a NTFS partition as common data share.

My config is the same as @bobbyprajan and @TEUser2K1 have mentioned. I have a Thinkpad running PopOS and Windows 10 in a dual boot config. It has two drives. I've kept the NVME drive as the data drive having NTFS partition. It doesn't have an OS on it. So in case I mess up the OS drive I can still have my data safe. Linux can access the data on the NTFS drive.
Decide how much space you will need for the Windows install on the system drive. It is relative and depends on the no of programs that you are going to install, Windows updates etc. In the remaining free space you can install the Linux distribution you want. Way back you would have to install Linux to explore its features but with the concept of a Live CD/ISO booted you can explore all the features of the distribution. Explore Ventoy which allows you to boot ISOs from any USB drive.
Enjoy your foray into Linux. Don't give up early as on Windows one takes many things for granted and getting things working could be little tricky on Linux. Try out PopOS, Linux Mint, Linux Mint Debian edition. Ubuntu was my Linux distribution of choice but with them trying to push snaps, I decided to explore other distributions.
Good luck

My multi boot settings are 1 SATA SSD per OS, for complete isolation between them, each OS has it's own bootloader on the same drive, and every OS doesn't know about other OS's.

I have bios settings profiles setup in a way that, each profile has only 1 Boot SSD enabled and others disabled. So to switch OS's I don't rely on any particular bootloader, I just switch profiles in the bios settings.

I use refind as my bootloader which can boot multiple OS. As long as the OS installer puts its boot files in the EFI partition there is no issue.You dont need to depend on the OS specific bootloader at all. I would have atleast 4 or 5 distributions installed in my system and refind has no issues booting them up. You can install refind from windows or from most linux distributions as a package. When an OS install changes the boot order, you can revert it either by going to the Boot settings in the UEFI or using "efibootmgr" in any linux installation

These days we have EFI, so boot loaders don't overwrite one another. Also data can be read through drivers even if os is installed in another disk. They are all visible.

I have both OS installed on same nvme - 1 partition for windows and 1 for linux. I install essential programs within these, but large stuff like steam library gets installed on another partition. That makes it simpler to take backups and for reinstalls. Linux partition can be encrypted ( LUKS ). ~65gb seems to be enough for windows.

Also if you are using steam on linux, then installing games on ntfs does not work for me ( not sure if it can be enabled). By default we cannot execute stuff off ntfs partitions. So i also have separate ext4 partition for steam library.

Finally, if ever in doubt about something in Linux - Arch wiki is very good.

bobbyprajan said:

Other than the OS partition of Ubuntu keep all other partitions NTFS. Linux can read and write NTFS partitions just fine

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Linux cannot use NTFS for
/boot
/home

Those will have to stay in ext4 or xfs or whatever the OS supports.
Additionally any installed application/game on linux has to go into a drive which is using the above type of file systems.
NTFS can only be used for static data storage/dump.

> Windows on 1TB SATA using NTFS; will be used mostly for gaming, watching films, etc.

Gaming should've been better on ssd ?

> this sounds interesting; first time I've heard of this. Any reason to this? Isn't it quite a few steps to have to enter BIOS & change profile every time you want to switch the OS?

Considering you have two storage devices, many systems allow bios itself to prompt to select which storage device to initiate booting from. If your system allows such an option, that will be better I think, can even boot from default partition after waiting few seconds. No additional dependencies, mbr / boot sector overwrite issues, etc.

Also, Linux don't have much issues reading and writing to NTFS, but that is for general data, not for Linux's OS system usage. This is how my understanding goes.

TEUser2K1 said:

Considering you have two storage devices, many systems allow bios itself to prompt to select which storage device to initiate booting from. If your system allows such an option, that will be better I think, can even boot from default partition after waiting few seconds. No additional dependencies, mbr / boot sector overwrite issues, etc.

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To repeat, mbr overwrite issues are no longer a problem with EFI. Unless this is an old system, it would be much better to use EFI/GPT instead of legacy mbr. EFI has its own extra partition and each os installs whatever it needs to in its own folder without overwriting other.
Also, Resizable BAR/amd smart access memory requires new way.

I use grub from linux to boot into either os. grub automatically detects windows. You may need to run update-grub once after installing linux. This way there is no need to select os from bios, i select linux as default in bios which loads grub which can load either os.

Also, disable hibernation in windows or atleast disable fast boot. Otherwise linux wont be able to read ntfs partition, or will cause corruption. Fast boot does not flush stuff to disk i think.

> mbr overwrite issues are no longer a problem with EFI

Theoretically I know this very well.
Had a bad experience with Windows mangling grub settings on my work laptop, got into some fuss, I stopped depending on bootloaders after that forever.
Will prefer to keep things simple whenever possible.

TEUser2K1 said:

Theoretically I know this very well.
Had a bad experience with Windows mangling grub settings on my work laptop, got into some fuss, I stopped depending on bootloaders after that forever.
Will prefer to keep things simple as possible whenever possible.

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Could be wrong, but i don't think this is possible anymore with EFI, thats my point.

You likely had issue with mbr system which uses starting sectors of hard disk for boot info. This is not relevant anymore.
At best, windows/bios might change the boot order which i think happened once to me after windows install on old motherboard.

I have had boot loader issues many time before. Not once with UEFI. Not once has windows messed up linux and vv for me.
With mbr method, we had to either take a backup of mbr before installing windows or reinstall grub from live cd using fakeroot.
Never needed it again once i started using EFI.

Note that disks have to be in gpt format before installing os. Once we install with mbr it becomes more difficult to switch to efi.

EFI is very simple. Just need to be familiar. Disable legacy support in bios, install windows, let it create EFI partition etc. Then install linux, make sure it uses EFI partition by marking as EFI ( probably does by default, dunno). After install, select linux as default boot option in bios. Boot into linux and run update-grub if windows is not part of bootloader options. Done

Anyway, either works and what seems simple is perhaps influenced by what is familair. OP can experiment and decide. EFI is the modern way of doing things and some gpu features requires it.

No harm in installing into two separate disks whether through mbr or uefi.

Though this happened sometime back, uefi was very much enabled. Some confusion about enabling secureboot too.
Tried luck with reinstalling grub, etc. but my googlefu was not enough. Reinstalled Windows OS, got some side eyes from my supervisor for using Linux (only used Fedora) causing inconvenience and time-waste, though I was the one working on all of this, haha.

BullettuPaandi said:

this sounds interesting; first time I've heard of this. Any reason to this? Isn't it quite a few steps to have to enter BIOS & change profile every time you want to switch the OS?

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Suppose you want to install 3 different windows OS, and you have three different sata SSDs which are formatted. If I don't disable any SSD in bios (a.k.a disabling sata port only) and start installing windows on SSD A, what will happen is it will install bootloader + windows on SSD A, now if I begin to install windows again on SSD B, what will happen is it will install only windows and add it's entry into bootloader on SSD A, similarly when I install windows on SSD C, it will install only windows and add it's entry into the bootloader on SSD A.

So when we install windows it first detects if there is a bootloader on any storage device, if not found, then it will install bootloader with windows.

Up until now I have setup like this.
SSD A - Bootloader + windows
SSD B - windows only
SSD C - windows only

If anything happens to SSD A, then windows on SSD B and SSD C will not be able to boot, because there is no bootloader on system. Also if you want to install clean windows again on SSD A for some reason the previous bootloader will get wiped and with it the entries for windows on SSD B and SSD C will also get wiped, so they won't be able to boot.

So solution to this problem is :-
Before installing windows disable other drives where you want a different operating system to be installed and also disable drives where an operating system already exists. This way the installation will not find any bootloader nilly willy and it will always install bootloader + windows on the selected storage drive.

With this setup you will always end up with
SSD A - Bootloader + windows
SSD B - Bootloader + windows
SSD C - Bootloader + windows

This is where complete isolation between operating system is achieved, no matter what happens to any OS, your other OS's will always work. You don't give any particular bootloader all the power to manage all your operating systems, instead you go one step lower and handle boot selection in the BIOS itself manually.

Yes it involves more steps to select your operating system, but BIOS have profile options which are easy to switch, you pre populate your profiles with only one boot drive enabled, along with it you can enable those drives (which don't have any operating system, just have data) which you want to show up in all your operating systems, or maybe you want some drives to show up only on certain operating systems, you get complete control.

You decide in your BIOS that which operating system will get access to what storage drives.

This example is targeting windows OS's but you can also mix other operating systems there is no difference.

The only requirement is 1 sata drive per operating system and you are good to go. This also frees you from partitions and their types.

This method is my own, it's nowhere on the internet I believe.

Heisen said:

Suppose you want to install 3 different windows OS, and you have three different sata SSDs which are formatted. If I don't disable any SSD in bios (a.k.a disabling sata port only) and start installing windows on SSD A, what will happen is it will install bootloader + windows on SSD A, now if I begin to install windows again on SSD B, what will happen is it will install only windows and add it's entry into bootloader on SSD A, similarly when I install windows on SSD C, it will install only windows and add it's entry into the bootloader on SSD A....

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I agree, this is the best way to do it. Only problem is when you have multiple nvme drives. My bios does not let me disable those, so you have to manually remove them.

variablevector said:

I agree, this is the best way to do it. Only problem is when you have multiple nvme drives. My bios does not let me disable those, so you have to manually remove them.

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Exactly this is why I mention only SATA SSDs, bios let's you disable SATA ports.

Never risk installing different OSes from different brands on a single storage for the obvious complex issues arising further.

In windows, you can play installing multiple windows only variants on a single storage due to the common bootloader and envi. windows platforms share in common.
But when installing Linux, ubuntu, mac etc. are all better off on different physical storages.

I had experimented in the past mixing windows with different linux flavors, but the key was to first install linuxes and in the end windows so that windows gives that dual, triple or quadruple booting options to choose while booting the pc. I'm sure linux has now highly matured to not to mess with other OSes yet offering such booting options.