Ubuntu on MacBookPro - difficulties w partition tables

[david.macquigg]

Ubuntu on MacBook is horribly unstable

The problem is in rEFIt, not Ubuntu. Ubuntu installed easily in VirtualBox on my MacBookPro, and I've had no problems since installing it two weeks ago. See my earlier post.

[tpievila]

I've had no problems since installing it two weeks ago. See my earlier post.

Could you post your MBR and GPT tables so that I could try reversing whatever damage gptsync did?

[srs5694]

Could you post your MBR and GPT tables so that I could try reversing whatever damage gptsync did?

You may want to read my Web page on hybrid MBRs, perhaps in conjunction with other pages in my GPT fdisk documentation, and perhaps the Wikipedia entry on GPT. You could also post those partition tables here, as revealed by "sudo fdisk -lu /dev/sda" and "sudo gdisk -l /dev/sda" (the latter will require you to install GPT fdisk from the gdisk package).

[david.macquigg]

TP, you don't need to fix any unsynchronized partition tables. You don't need disk partitions at all. Just remove the new partition entirely. VirtualBox installs within the existing partition.

Is there some reason you want to use partitions? Even if we get the current problems fixed, new problems will arise as the dominant vendors (Microsoft and Apple) try to hog the machine and make life difficult for competing systems. VirtualBox seems to have avoided these problems.

[tpievila]

Rod: Your pages were invaluable, and I indeed had already read them. The problem was that I wasn't really aware what rEFIt expects to find, and that wasn't documented. In the end I read the source code to understand the behaviour I was getting. Thank you for the great tool you made.

David: I would have responded already earlier, but flaky GPRS in train ate two of my replies earlier. But what you are suggesting is that I, nor many others do not understand what they want and that our questions and problems are invalid. When the question is "How can I do A?", answer "Well, you should be doing B anyway" is not helping at all. I already do, and did have Ubuntu running virtualized. But that wasn't often good enough and didn't solve any problems I had with OS X annoyances.

Running Virtualbox won't stop configd from locking up twice a day when running mobile broadband. Running Virtualbox won't stop the Apple X11 from refusing connections after mysterious events. Running Virtualbox won't give me back the memory that booting into OS X took when I wanted to get into Ubuntu, nor dozens of other reasons to change OSes. I was fed up with OS X, and wanted Linux. Instead of, not in addition to.


For what's it worth, I think I now understand the problem of Ubuntu on Macbook very well, and if anybody else is having problems, please contact me. I intend to document the whole process with all dead ends and frustrations soon, I just need to run a couple of tests to see what is ok and what will break the system (my suspicions go towards OS X doing anything to partitions after the multiboot has been set up and secondly towards using extended partitions while installing Ubuntu, which might confuse the gptsync badly indeed).

[srs5694]

For what's it worth, I think I now understand the problem of Ubuntu on Macbook very well, and if anybody else is having problems, please contact me. I intend to document the whole process with all dead ends and frustrations soon, I just need to run a couple of tests to see what is ok and what will break the system (my suspicions go towards OS X doing anything to partitions after the multiboot has been set up and secondly towards using extended partitions while installing Ubuntu, which might confuse the gptsync badly indeed).

If by "extended partitions" you mean MBR extended partitions with contained logical partitions on a hybrid MBR, then that is indeed a Very Bad approach. Keeping the GPT and MBR partitions synchronized in such a case would be a nightmare. I know of no utility that attempts to do the job. If such a utility ever emerges, I personally would consider it bordering on malware, the practice would be so bad.

Since Linux understands GPT perfectly well, my personal preference would be to use a conventional GPT when installing Linux on a Mac, unless Windows is also involved. Unfortunately, I don't know if the Mac boot process, including the commonly used boot loaders like rEFIt, can handle that. There could also be Ubuntu-specific complications, particularly with respect to installation, since installers sometimes impose limitations that can be overcome once the OS is installed.

[inphektion]

without reading this whole thread i can tell you right now that directly after the hfs+ partition mac wants a small 100-200mb slice. its not formated anything just empty. if you boot into mac mode and re-bootcamp a large partition you'll see it created again. Instead of deleting the bootcamp part and that little chunk and re-partitioning i just carved up the bootcamp piece. without that little piece there you can't upgrade mac osx ( i was stuck on leopard for a while which i why i know of this).

I'm having difficulty getting Ubuntu installed on my MacBookPro. Following the instructions at https://help.ubuntu.com/community/MacBookPro3-1/Lucid, I seem to end up with messed up partition tables. I see several suggestions in the Ubuntu forums, including give up and use VirtualBox, but before experimenting any more, I would like to know if there is a simple fix. Ubuntu installed nicely on my desktop (Generic PC > XP > VirtualBox). It should be just as easy on a Mac. I must be doing something wrong.

---------  My laptop
MacBookPro3,1 with Intel Core 2 Duo and Mac OS X 10.5.8.
---------  CD to install
ubuntu-10.04.1-desktop-i386.iso, verified.
---------  Links where I found useful information
https://help.ubuntu.com/community/MacBookPro
https://help.ubuntu.com/community/Ma...elInstallation
---------  Step-by-step instructions I attempted to follow
https://help.ubuntu.com/community/MacBookPro3-1/Lucid

---------  Install log                                       9/10/2010
#     My comments.
#err  Notes where there seems to be errors in the instructions.

Boot Camp Assistant (Applications/Utilities)
  Partition the HD:         88  :   60  GB
  # 60GB partition is labelled "Windows", no choice here.

Install rEFIt-0.14.dmg from refit.sourceforge.net
  Running on:
    EFI Revision 1.10
    Platform:  x86_64 (64bit)
    Firmware:  Apple 1.10
    Screen Output:  UGA Draw (EFI 1.10), 1440 x 900

Boot from CD
  System > Administration > Partition Editor
#err  Partition Editor is not on menu.  Used GParted instead.
  Delete new partition /dev/sda3.
  # Now have:
  /dev/sda1   fat32   EFI     200.00 MB     boot
  /dev/sda2   hfs+             87.88 GB
  unallocated                  60.98 GB

Install Ubuntu from CD
  dave-laptop
  ext4 filesystem
  install to "largest continuous free space"
#err Skip the advanced "install grub to /dev/sda3."  /dev/sda3 not on the list.

Fix the Partition Tables
  Select "partition tool" from rEFIt menu
  # Response is different than expected.  Screen says
  "Starting gptsync.efi"
  Current GPT partition table:
  ...
  Current MBR partition table:
  ...
  Status: MBR partiton table is invalid, partitions overlap.
  Error: Not Found returned from gptsync.efi 
  # This might have something to do with skipping the grub install above.

#err  Cannot fix the partition tables, as directed in help document.  There
#err  is no option to do so.  Hitting any key returns to the rEFIt menu.

# Cannot boot to Ubuntu from rEFIt menu.  System just freezes.

Try again install from CD.
Hold "c" while booting.
Select "Install Ubuntu" from menu.

# Ubuntu installer shows current partition table as:
  fre space                0     MB
  /dev/sda1   fat32        209   MB 
  /dev/sda2   hfs+         94355 MB 
  free space               1     MB
  /dev/sda3   biosgrub     1     MB
  /dev/sda4   ext4         62758 MB
  /dev/sda5   swap         2715  MB
  free space               0     MB

# What is biosgrub?  Maybe this is causing the problem.
Delete all partitions after /dev/sda2.
# Cannot save modified table.  Error says "No root file system is defined.

Try instead with GParted
Boot from Ubuntu CD.
System > Administation > GParted
Delete all partitions after /dev/sda2.
  /dev/sda5 has a lock icon, which needs to be removed by clicking
    Partition > SwapOff

Install Ubuntu from CD
Restart
rEFIt now shows two Linux systems (HD and CD)   ???

Install Ubuntu from CD
  install to "largest continuous free space"
  dave-laptop
  ext4 filesystem
  Advanced: Install boot loader on /dev/sda        ???
# Install looks normal, but restart crashes out.

Second restart OK.
Start rEFIt partition tool.
# Same error as before - partitions overlap.
Back to rEFIt menu.
Boot Ubuntu from HD.  Hangs at startup screen.

Boot Ubuntu from CD.
# Ubuntu installer shows partition table identical to above, including 
# biosgrub.

[david.macquigg]

Running Virtualbox won't stop configd from locking up twice a day when running mobile broadband. Running Virtualbox won't stop the Apple X11 from refusing connections after mysterious events. Running Virtualbox won't give me back the memory that booting into OS X took when I wanted to get into Ubuntu, nor dozens of other reasons to change OSes. I was fed up with OS X, and wanted Linux. Instead of, not in addition to.

TP, thank you for at last answering my question why anyone would prefer dual boot over VirtualBox. I have not encountered these problems myself, but that may be because I am not pushing the limits. I still have Mac OSX 10.5 as the main system on my MacBookPro.

Sorry for suggesting B when your question was - How do I do A? My understanding was that our objective (A) was simply to get Ubuntu running on a MacBookPro.

I encourage your efforts to "document the whole process with all dead ends and frustrations soon". A wiki page would help get that started, and encourage others to participate. What is lacking in the current documentation is a good overview of the alternatives (VMs vs partitioning). We waste a lot of time pursuing what seems like the simpler option (partitions) only to find that this option has hidden problems, is not well supported, and may even be fighting what Apple wants - to weld their OS to their hardware.

I suggest that the basic choice of VM vs partitions be discussed in the first paragraph. Then describe in some detail the problems you have encountered with one of the VMs (VirtualBox). For example, what program are you using for mobile broadband? It might be that someone using a different program doesn't see these problems, and they could add a note to your wiki page. There might also be some settings in VirtualBox that could solve the problem. Mac OSX is one of their supported platforms, and we might get some help on their forums.

There must be a dozen different ways to get Ubuntu running on a Macbook. We need a well-organized tree of choices in our documentation.

[srs5694]

without reading this whole thread i can tell you right now that directly after the hfs+ partition mac wants a small 100-200mb slice. its not formated anything just empty. if you boot into mac mode and re-bootcamp a large partition you'll see it created again. Instead of deleting the bootcamp part and that little chunk and re-partitioning i just carved up the bootcamp piece. without that little piece there you can't upgrade mac osx ( i was stuck on leopard for a while which i why i know of this).

It might be worth reviewing Apple's Secrets of the GPT Web page, and particularly the "Advice for Partitioners" section. This section lays out how Apple recommends partitioning disks. I suspect the "100-200mb slice" to which you refer is actually an unpartitioned part of the disk. (The use of the word "slice" should be avoided when referring to unpartitioned space, since that word is synonymous with MBR partitions in some contexts, such as among BSD users.) Apple recommends putting 128 MiB of empty space after most partitions, and Apple's GUI Disk Utility enforces this. Without it, Apple's installer may refuse to install or upgrade the OS. Linux isn't fussy about this issue.

Another requirement is an EFI System Partition (ESP), which Apple creates as a 200 MiB partition. IIRC, the EFI spec says the ESP should be 100-200 MiB in size.

Incidentally, that document (written in 2006) is pretty firm (as is the EFI specification) in saying that the MBR of a GPT disk should contain one MBR partition, of type 0xEE, that covers the whole disk (or as much as MBR size limits permit). In other words, hybrid MBRs are verboten. It's ironic that Apple itself began pushing hybrid MBRs as a way to make its Boot Camp work, thus creating a whole string of problems down the road -- the very problems they warned about in their 2006 "Secrets of the GPT" document!

[tpievila]

It's ironic that Apple itself began pushing hybrid MBRs as a way to make its Boot Camp work, thus creating a whole string of problems down the road -- the very problems they warned about in their 2006 "Secrets of the GPT" document!

Regarding this and your earlier comment about pure GPT setup: According to the rEFIt documentation (http://refit.sourceforge.net/myths/), Linux currently needs BIOS or equivalent emulation mode to get accelerated 2d/3d, and at least in Intel Macs the only way to get into this mode is to boot the "legacy OS" via MBR. This is where my knowledge is second hand at best, but at least Google nor IRC could find any indication that this info would have been superseded (unfortunately). Would be great to find someone who actually knows why this is, and if anything can be done about it.

To get started on the documentation I still need to find out what exactly can cause the multiboot setup to break. After the last time I wrote here, I've also gotten a scary new bunch of error messages from rEFIt about not finding volumes and what not, but after clicking "any key to continue" it still gets to the boot menu and can boot to Ubuntu. Didn't try OS X during the weekend for the fear of breaking the whole thing down while away from home and my other computers.