Running Arch Linux on iMac late 2013 (27 inch)

What did I do with my iMac?

Finally, I got bored with macOS.

I bought my first Mac computer in March 2014, which is a 27-inch iMac. I liked it, so I bought another MacBook Pro, and I’ve been using macOS since, until about a week ago.

I installed Arch Linux on my iMac, and here are some highlights:

• It uses EFI boot, using GPT partitioning on one 1T HDD.
• It is running ZFS on the root partition.
• It is using dm-crypt for full-disk encryption.
• It is using an Nvidia 775M, driving 2 external 1440p monitors, so 3 x 1440p monitors in total.

The installation process

It was challenging and fun

I am not going to list a step-by-step guide, as the way I did it may not be the way you want your system to be, and I believe as an Arch Linux user you are not expecting a step-by-step guide, are you?

To be able to install them properly, I would suggest you carefully read the Arch Linux wiki pages about these few things:

• ZFS (https://wiki.archlinux.org/index.php/ZFS), especially the root on ZFS section.
• dm-crypt (https://wiki.archlinux.org/index.php/Dm-crypt), this is used to encrypt your disk.
• rEFInd (https://wiki.archlinux.org/index.php/REFInd), to help you understand how EFI booting works.

Also you may want to learn a little bit more about ZFS before you start:

• The Z File System by Allan Jude (http://www.allanjude.com/bsd/zfs.html)
• ZFS Primer by FreeNAS team (https://doc.freenas.org/9.3/zfsprimer.html)

The idea is like this

1. You want to use rEFInd to boot to a FAT32 partition, looking for a config file /boot/refind_linux.conf.
2. The config file will tell dm-crypt that this is an encrypted drive, so the kernel will load dm-crypt and you will be asked to enter your password.
3. Then after dm-crypt maps the drive to a virtual device like /dev/mapper/something, ZFS will start to import the pool, and mount different partitions accordingly based on mountpoint settings.
4. After ZFS mounts your root, your system will then boot successfully.

The result

In general it’s pretty good.

• I am running Gnome. I was going to try KDE, but it crashed every time I wanted to unlock a panel… Therefore… zfs rollback ...
• Most of the devices just work, including Wi-Fi, Bluetooth, camera, microphone and speaker. Even the 3-monitor config works out of the box if you install the nvidia driver that ships with Arch Linux.
• Suspend and wake-on-LAN are both working out of the box.

Only one thing before I can say it’s perfect:

• Switching between the speaker and headphones does not work perfectly. Sometimes I try to unplug the headphones but the speaker still does not make any sound (even though Test Speakers works), but after a while it’ll be back again.

In conclusion

I know I am running Arch Linux (lovely rolling release distro) on an iMac (super Linux “friendly” hardware), but I’ve got ZFS, so if the update ruins anything, zfs rollback ....