Im currently struggling with new hardware and installing ubuntu in a first step on it (16.04 daily builds), where macosx will follow.


  • Supermicro x10DAi
  • dual xeon
  • firmware: UEFI

The following descibes my hardware setup im trying to install ubuntu to:

sda 1x HDD for /home

sdb 1x HDD for /usr (for several needed apps thats going to be installed to /usr and will take a huge amount of diskspace)

sdc 1x SSD for / (linux)

sdd 1x SSD for EFI and bootloader (for dualboot linux and macosx)

sde 1x SSD for / (macosx)

As of this setup i need to configure the partition by myself which in general isnt a big deal but somehow im always getting the grub shell (where i think i would need another bootloader because of linux and osx installed aside) when rebooting.

What i did during partition:

Partition sda1 in XFS and set mountflag to /home (full disk)

Partition sdb1 in XFS and set mountflag to /usr (full disk)

Partition sdc1 in swap and set swap flag active (3GB) Partition sdc2 in XFS and set mountflag to / (rest of sdc)

Partition sdd1 in EFI (1GB)

The macosx partition sde is not formatted because the osx system will be installed in a sec. step.

Ubuntu let me choose where to install the bootloader and i choosed sdd.

Ubuntu 16.04 choose bootloader device

Aside im getting format error messages during installation for sdd (its a brand new ssd by the way) the installation went smoothly. After restarting im always found myself in a grub shell.

Inside grub shell an ls brings up some error: failure reading sector 0xXXX hd1

However i decided to setup the hardware the same but let the installation target for the bootloader be sda instead of sdd and voila the system boots...

My questions are:

  1. Why is grub not able to install itself to sdd, or is my partition setup faulty?
  2. How can i proper format sdd and install the EFI partition and a bootloader (which is able to boot linux and macosx) to sdd so that this disk will be able to boot ubuntu linux and macosx (a bootdrive)?
  3. If this could be done: from what i read about UEFI i dont need to setup another EFI partition when reinstalling linux (just setup /, /home, /usr and im done), is that correct?

If i had missed some useful information here please let me know and i will try to bring them.


Summary of EDIT 1:

  • Edited title to make more clear im going to dualboot linux and macosx
  • Added the disk information for the later to be installed macosx installation
  • Added screenshot from "Device for boot loader installation"
  • Added screenshot from verifying UEFI boot
  • Added information why /usr would be a seperated hdd instead of / on ssd

First, your partitioning is wasteful. A basic installation requires one partition, for root (/). (Another may be needed for the boot loader; more on that later.) In this configuration, all directories and subdirectories are on this partition. When you create another partition, it's mounted somewhere that you specify in this directory tree, thus relieving some of the space requirements on root (/) and enabling various benefits.

The problem with your setup is that devoting an entire disk to some of your partitions is wasteful:

  • /usr is not likely to hold more than about 20 GB of files. These files are the bulk of the Linux system, so putting /usr on a hard disk and root (/) on an SSD will actually degrade performance compared to putting both on the SSD. The only reason I'd do this is if the SSD is tiny -- and such a tiny SSD suggests an old one, which might no longer be reliable.
  • The EFI System Partition (ESP) holds just a few megabytes of files, but for various reasons related to EFI quirks, I recommend making it 550 MiB or larger -- but certainly not big enough to devote a whole disk to it, assuming a non-ancient disk. Furthermore, the ESP is used only at boot time or when updating the boot loader. Thus, devoting an entire SSD to the ESP means throwing away the SSD's speed benefits.

A better plan is to use your SSD(s) for a root (/) filesystem without a separate /usr filesystem, to put /home on your hard disks, and to create a separate ESP wherever it's convenient. If you want to use all four of your disks, you should seriously consider using Logical Volume Management (LVM), which enables combining multiple partitions (physical volumes, in LVM-speak) into one volume group, which is then carved up into logical volumes that hold your filesystems. (Note: Logical volumes are not the same as logical partitions, which are an unrelated MBR partitioning construct.) You can therefore create a single big logical volume that spans multiple disks. Controlling the split between your SSDs and hard disks requires more advanced LVM techniques, or you could create two volume groups, one for your hard disks and one for the SSDs.

Ubuntu let me choose where to install the bootloader and i choosed sdd.

When installing in EFI/UEFI mode, the Ubuntu installer does not prompt for where to install the boot loader. Instead, it detects the ESP and automatically installs the boot loader there. Thus, I suspect you may have accidentally booted in BIOS/CSM/legacy mode. See my page on the CSM for further information on this topic, including tips on controlling how you boot.

This problem may well be why you received an error when installing GRUB. In a BIOS-mode install, GRUB works best with a BIOS Boot Partition, which you probably didn't create. If it's not present, the Ubuntu installer will complain. I can't be sure of this, though, because you haven't said what the error message was. (Side note: When asking for help, always present the complete error message. Nine times out of ten, summaries omit the most important details.)

That said, I'm not sure what caused the error: failure reading sector 0xXXX hd1 message you report getting from GRUB. It could be related to the installation error, or it could be that your disk is defective.

Is there a way i could format sdd and install the EFI partition and a bootloader (which is able to boot linux and macosx)

Hold the phone! Are you saying this is a dual-boot with OS X? If so, that's a critical detail, and detailed information on your partitions is required to give a coherent answer to your question. Please post that information. (The output of sudo parted -l should do the trick. Be sure to edit your original question; do not try to cram that information into a comment -- but do add a comment to this reply so I'll be informed of your new information.)


In EFI mode, typing sudo grub-install causes it to install to the ESP (I believe the one mounted at /boot/efi by default, but I'm not 100% positive of that). Thus, there's no need to specify a disk device. Certainly it's not installed to a whole-disk device, but to a partition. Thus, any prompt you're seeing in the Ubuntu installer about this is misleading. It's possible that the system is getting confused because you've got so many disks, and it would work better if you'd create an ESP on /dev/sda.

Dual-booting a standard PC (you say it's a Supermicro board) with Linux and OS X is tricky at best. This practice is even of debatable legality in many countries. I don't know what this forum's policy is on discussing the topic, but certainly, when you get to actually configuring that part of it, you're better off asking on a Hackintosh-specific forum.

Using a separate /usr partition used to be common practice, but is rare today. I don't know offhand if Ubuntu even supports this configuration any more. If it does, it shouldn't take anything particularly special to set it up; however, I advise you to be very certain about where the huge program files you're anticipating will go. Even a heavily-loaded Ubuntu system is unlikely to need more than 20-30 GiB of disk space. Many big programs store their files in users' home directories or in particular subdirectories that might be better split off. Doing this may be better than putting /usr on your hard disk, since you'll see a speed drop when you do that. If you could say what programs you're installing that require massive amounts of space, perhaps somebody could offer better guidance on this score.

  • Dear Rod, thanks for taking the time to reply to me. Sorry if my initial title and question was misleading. I tried to edit the title and question more proper and added an edit summary. All done in my OP. I hope that there is some more useful information in now and you would be able to help me out of this – user252296 Mar 2 '16 at 17:46
  • Please see my edits, above. – Rod Smith Mar 2 '16 at 23:48

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