Install Using GPT on x86_64 BIOS by Default
This document represents a proposed Change. As part of the Changes process, proposals are publicly announced in order to receive community feedback. This proposal will only be implemented if approved by the Fedora Engineering Steering Committee.
Summary
This Change makes it so that Fedora Linux systems installed on legacy x86 BIOS systems will get GPT partitioning by default instead of legacy MBR partitioning. This makes x86 BIOS installs more similar to x86 UEFI installs.
Owner
- Name: Neal Gompa, Davide Cavalca, Michel Alexandre Salim, Chris Murphy
- Email: ngompa13@gmail.com, dcavalca@fb.com, michel@michel-slm.name, chrismurphy@fedoraproject.org
Current status
- Targeted release: Fedora Linux 37
- Last updated: 2022-05-14
- devel thread
- FESCo issue: <will be assigned by the Wrangler>
- Tracker bug: <will be assigned by the Wrangler>
- Release notes tracker: <will be assigned by the Wrangler>
Detailed Description
Once implemented, Anaconda will create a GPT disk table on non-partitioned disks or when the disk is being completely reset when Fedora x86 install/live media is booted in BIOS mode.
Feedback
Benefit to Fedora
This simplifies our default code path by using the same partitioning scheme as UEFI systems and aligns us more to how Fedora variants that are delivered as disk images, which all use a similar setup. It also paves the way to implement hybrid BIOS+UEFI boot for legacy BIOS installs to enable future conversion to UEFI boot or emulated UEFI boot on legacy BIOS.
This is a step toward a longer transition to eventually eliminate direct BIOS boot support, as identified in the discussion for the rejected Change to deprecate BIOS support in Fedora Linux 37.
Scope
- Proposal owners:
- Submit code changes to Anaconda to use GPT by default on BIOS systems (gh#rhinstaller/anaconda#4104)
- Other developers:
- Anaconda developers need to review and merge the pull request
- Release engineering: #10796
- Policies and guidelines: N/A (not needed for this Change)
- Trademark approval: N/A (not needed for this Change)
- Alignment with Objectives: N/A (not needed for this Change)
Upgrade/compatibility impact
There will be no impact for existing Fedora Linux systems that upgrade. We will not convert the partitioning on upgrade. However, some very old systems have buggy EFI implementations that do not handle legacy BIOS boot on GPT well, and on those systems, users will need to request Anaconda to create a legacy MBR partition table by using inst.mbr on the boot command-line.
How To Test
Currently, users can test by booting Fedora media on BIOS systems with the inst.gpt option to try installing Fedora Linux on a legacy BIOS boot system with a GPT disk. After the change is merged and released, this behavior will be the default, and inst.mbr would be required to go back to the previous behavior.
User Experience
In general, there should nothing materially changing for users. If users look at the disk with fdisk or parted, they'll see a GPT disk instead of an MBR one and a BIOS boot partition will be present, which stores the GRUB boot code on a GPT disk.
Dependencies
This is isolated to Anaconda and is principally dependent on getting the changes into Anaconda.
Contingency Plan
- Contingency mechanism: Revert the change in upstream Anaconda
- Contingency deadline: Final Freeze
- Blocks release? Yes
Documentation
The upstream documentation will be updated as part of the change in Anaconda.
Release Notes
Fedora Linux now uses GPT (GUID Partition Table) partitioning by default for x86_64 systems that use legacy BIOS instead of UEFI. This brings a more modern method of partitioning disks and aligns closer with UEFI-based installations, which already use GPT partitioning.