I have a server whose motherboard does not have UEFI, so that means the OS must be installed on an MBR table. MBR has a limit of 2 TB, so I'm wondering if I can install Windows Server on a boot drive that's less than 2TB and have multiple other drives that are higher than 2TB (non boot drives). Can I have multiple partition tables in the OS like that? with no UEFI, will I be able to install multiple drives greater than 2TB? Does BIOS matter when installing non boot drives at all? I'm not planning on doing RAID, but if I do raid, does this mean all drives must be 2TB max due to the boot drive only being 2TB?
If the motherboard does not support UEFI BIOS, can I still use GPT for non boot drives
gptguidmbr
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@Ramhound: Mac OS X only requires a GPT partitioning scheme to INSTALL, it will boot from MBR if your copy the OS to such a disk.
@John: The simple answer is no, you can't. Here's why.
You should not convert a Windows installation in place, you should instead install from scratch. This is one of those problems where you would spend more time making copies of your data, and technical massages of the machine to get it to do what you want than simply reinstalling.
Windows does not care about not boot disks, so you can make your secondary disk into a GPT disk if you want to. You would have to do this if you had a 3TB drive anyway. Now, there are no easy tools to convert in place, you would be wiping the drive clean to change to GPT. (Remember, GPT and MBR are the underlying structure of the partitioning scheme, so by changing them, you are wiping the partition table clean.
Now, you were not clear on your usage of Hyper-V, is your system installed on top of Hyper-v? If so, then the answers change, because your system can be "copied", reinstall Hyper-V onto the GPT disk, then "copy" the system back, and you don't go through the reinstall process.
This is not how most people use there computer, but you mentioning these system makes this a possibility.
Sorry I can't be more positive.
Google searches turned up tips like "you have to boot the DVD drive in UEFI mode to install OS on UEFI", etc. This made me believe that I have to convert my USB drive to GPT just to install an OS on an UEFI machine.
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Why does the installer say it's impossible to install a UEFI-booted OS from a MBR-based USB drive? Can't it create new UEFI boot options while being booted from MBR, or what?
Do not confuse booting from a GPT or MBR disk with booting in EFI or BIOS mode.
Normally these two requirements are not related. An UEFI system is required to support both GPT and MBR partition tables. (Likewise, BIOS systems don't normally read the partition table at all, and can easily boot from a GPT disk as long as the sector 0 boot code is capable of it.)
It is only Windows that refuses BIOS-mode boot from GPT disks, and EFI-mode boot from MBR disks. And, well, some buggy BIOS systems do choke on "protective" GPT MBRs; likewise, some buggy UEFI systems do think "MBR = legacy boot".
But, aside from that, your guess about creating boot options is correct. See below.
I mean, it's just files written to disk, does it really matter how the installer was booted? The machine will surely reboot during install and then it can use whatever mode it wants, if it think it's necessary.
No, it cannot. First, the boot mode is not chosen by the OS once booted; it is chosen by how the bootloader was installed. To set up a bootloader for BIOS, you write boot code to the 0th sector. To set up a bootloader for EFI, you add a boot option to NVRAM as an EFI "variable". Second, EFI runtime functions are only accessible when booted in EFI mode, and you need to use them in order to modify EFI variables.
So, if you're in BIOS mode, the installer cannot add a boot option to the NVRAM, and therefore cannot set up EFI-mode boot for the freshly-installed system.
So your assumption that it "can use whatever mode it wants" is incorrect.
(As a precaution, Windows does also install its own bootloader to the "fallback" path, \EFI\Boot\BootX64.efi, however, that path is used only if there are no working boot options in NVRAM. So if you don't add a boot option, there's a small chance that it'll still boot, but it's far from being a guarantee.)
I also get the impression that converting from MBR to GPT requires me to also delete my other partition on the USB drive. Thats a 1.97 TB partition and that's not acceptable.
There are tools that can do in-place conversion; the Linux gdisk being one.
However, even if you do delete a partition, this doesn't normally discard any data within it, so you can access it again if you immediately create a new partition at the exact same place. This is how the conversion tools work, after all. (Again, you might need Linux fdisk or gdisk in order to specify the start/end location precisely; many tools only expose 1 MB accuracy.)
Best Answer
Non-boot GPT disks are supported on BIOS-only systems
It is not necessary to boot from UEFI in order to utilize disks partitioned with the GPT partition scheme. Therefore you can take advantage of all of the features offered by GPT disks even though your motherboard only supports BIOS mode.
With Windows, as you've already observed, the only restriction of concern is that you must boot in UEFI mode if you want to boot from a disk partitioned as GPT.