Installing Alma Linux on Classic Mac Pro 2012: A Beginner's Guide

Here is a detailed step-by-step guide to install AlmaLinux on your cMP from 2012 using standard partition (not LVM).

Pre-Installation Preparation

1. Download AlmaLinux Installation Media:

   • Go to the AlmaLinux website and download the appropriate ISO image for AlmaLinux.

2. Create Bootable Media:

   • Use a tool like Rufus (Windows) or dd command (Linux) to create a bootable USB drive from the AlmaLinux ISO.

Installation Steps

1. Boot from the Installation Media:

   • Insert the bootable USB drive into your cMP.

   • Restart the iMac and enter the boot menu (usually by pressing Option or Alt during startup).

   • Select the USB drive to boot from it.

2. Start AlmaLinux Installation:

   • When the AlmaLinux installer starts, choose the option to start the installation.

3. Configure Installation Settings:

   • Language and Region: Select your preferred language and region settings.

   • Installation Destination: Select the drive where you want to install AlmaLinux.

4. Custom Partitioning Scheme:

   • Set Up Partitions:

     • Boot Partition:

       • Click on "Custom" partitioning.

       • Create a partition of size 1024 MiB, format it as EFI System Partition, and set the mount point to /boot/efi.

     • Boot Partition (For GRUB2):

       • Create a second partition of size 1024 MiB, format it as XFS, and set the mount point to /boot.

     • Root Partition (/):

       • Create a logical volume (used standard partition) with the desired size (e.g., 50 GB), format it as XFS, and set the mount point to /.

     • Home Partition (/home):

       • Create a logical volume (used standard partition) with the desired size (e.g., 200 GB), format it as XFS, and set the mount point to /home.

     • Swap Partition:

       • Create a logical volume (used standard partition) with the desired size (e.g., 79 GB), and set the type to swap.

   • Do Not Install Boot Loader:

     • Since you will manually configure GRUB, select the option not to install a boot loader during the AlmaLinux installation process.

5. Proceed with Installation:

   • Continue with the installation process. Follow the on-screen instructions to complete the installation.

6. Reboot the System:

   • Once the installation is complete, reboot the cMP.

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Since refind bootloader is already in place for Arch Linux on other disk, we should be able to choose and boot the Alma Linux.

Given the contents of the /boot/efi/EFI/almalinux/ directory, it should have already created the necessary GRUB configuration files. Here's a breakdown of what you must see:

Contents of /boot/efi/EFI/almalinux/ Directory

• BOOTX64.CSV: A file that can contain boot options in CSV format for the system's firmware to use.

• grub.cfg & grub.cfg.rpmsave: The grub.cfg file is the main GRUB configuration file. The grub.cfg.rpmsave is likely a backup of the previous GRUB configuration before a recent update or change.

• grubx64.efi: The GRUB EFI binary, which is responsible for launching GRUB from the EFI environment.

• mmx64.efi: The Machine Owner Key (MOK) management tool for secure boot.

• shim.efi & shimx64.efi: Shim is a simple EFI application that allows for chain-loading a signed bootloader (like GRUB) on systems with Secure Boot enabled.

• shimx64-almalinux.efi: A specific shim binary likely tailored for AlmaLinux.

Whether to Proceed with grub2-mkconfig

• Current Configuration: Since your system is already booting correctly using rEFInd and the GRUB files are present, running grub2-mkconfig may not be necessary unless you need to regenerate or update the GRUB configuration (e.g., after kernel updates or other changes).

• To Ensure Up-to-Date GRUB Configuration:

  • If you want to ensure that the GRUB configuration is fully up-to-date, you can run:

      sudo grub2-mkconfig -o /boot/efi/EFI/almalinux/grub.cfg
    

  • This command will regenerate the grub.cfg file based on the current state of your system (installed kernels, etc.).

• Backing Up:

  • If you're concerned about making changes, you might want to back up the current grub.cfg:

      sudo cp /boot/efi/EFI/almalinux/grub.cfg /boot/efi/EFI/almalinux/grub.cfg.backup
    

When to Run grub2-mkconfig:

• Kernel Updates: If you update your kernel, it’s a good idea to regenerate grub.cfg to ensure the new kernel is included in the boot options.

• Custom GRUB Changes: If you modify /etc/default/grub or add custom configurations, you should run grub2-mkconfig to apply those changes.

Conclusion:

Since your system is already working fine with rEFInd and the existing GRUB configuration, you don't necessarily need to run grub2-mkconfig right now. However, if you want to ensure everything is perfectly configured or after future kernel updates, running it can help keep the GRUB configuration up to date.