Changes/GPTforAllByDefault

Install Using GPT on all architectures by Default

This is a proposed Change for Fedora Linux.
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 is a follow-up for the Fedora 37 change which made GPT the default partition table for x86_64. This change proposes switching to GPT for the other supported architectures as well.

Owner

• Name: Vojtech Trefny
• Email: vtrefny AT redhat.com

Current status

• Targeted release: Fedora Linux 42
• Last updated: 2024-12-05
• [Announced]
• [<will be assigned by the Wrangler> Discussion 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

In Fedora 37 we switched to GPT as the default partition table (disklabel) for x86_64, for Fedora 42 we propose to make the switch for other architectures as well. Because GPT was already the default for ARM64 this means switching to GPT for ppc64le and s390x architectures when installing on an empty disk or when the disk is being completely reset during the installation.

Note: for s390x this applies only to disks where MSDOS disklabel is currently being used as the default disklabel, for DASD we'll continue to use the DASD disklabel.

Benefit to Fedora

Similarly to the previous change: simplifying the code path and making the same default across all architectures with as few exceptions as possible. Fedora CoreOS now also uses GPT as default on all architectures so this change will also unify our defaults.

Scope

• Proposal owners: Change Blivet to prefer GPT as the default partition table on all architectures. Proposed upstream pull request: https://github.com/storaged-project/blivet/pull/1322

• Other developers: No work from other developers will be needed.

• Release engineering: #Releng issue number

• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

• Alignment with the Fedora Strategy:

Upgrade/compatibility impact

This change will affect only new installations, no change to the partition table will be done during the upgrade.

Early Testing (Optional)

Do you require 'QA Blueprint' support? N

Early testing can be done by using the boot option inst.disklabel=gpt. This option tells the installer to use GPT disklabel so it can be used to make sure the system is compatible and will install and boot correctly with GPT.

How To Test

Any of the installer test cases (for example QA:Testcase_Anaconda_autopart_(use_all_space)_install) can be used to test this. Note that the installer will create a new partition table only when an empty disk is used or when all preexisting devices are selected to be removed, the partition table cannot be changed when existing partitions are being reused.

The expected result is that GPT will be used as the partition table type on s390x and ppc64le. sudo fdisk -l /dev/sdx can be used to verify that GPT was used by the installer.

User Experience

Users shouldn't notice any significant change other than the switch from MSDOS to GPT disklabel. Other than that the user experience during installation, booting or using the system shouldn't change at all.

Dependencies

There are no dependencies for this change, all work will be done in Blivet, the library that Anaconda uses for storage configuration.

Contingency Plan

• Contingency mechanism: Revert the change in upstream
• Contingency deadline: Final Freeze
• Blocks release? Yes