<SOLVED> GPT changes to MBR on Linux Mint 12 install

[lotharjade]

I am trying to do a fresh install of Linux Mint 12 on my new OCZ Vertex 3 SSD. I have a Biostar 8200 motherboard with an AMD processor.

I create a GPT (GUID) partition table, then convert the whole drive to ext4 (to make sure it is all clean). Then I install Linux Mint 12 from a USB stick using the installation program. When I reboot in the new system, it is all in a MBR partition table, and not GPT. Why is it changing to MBR? How do I get a install of Mint with a GPT partition table???

[xenopeek]

Just to be clear; did you let Linux Mint installer setup its own partitions, or did you during installation choose to manually setup partitions, and then just configured it to use your pre-made partitions? It sounds like you did the former.

[lotharjade]

Ok xenopeek, your question helped me figure out how to solve this. I was using the automatic installer completely.

How I solved this, was I formatted the drive, and created a GPT partion table. Then after spending HOURS trying to match the partioning that the linux installer did automatically (with a MBR partition table). I finally figured out after searching that GPT DOES NOT USE EXTENDED PARTITIONS!!!
DOH!!! *slaps hand to forehead* How much time did I waste before I figured that out. oy!

Anyhoo... I created two partitions. One ext4 primary partiton (most of drive), and one linux swap primary partition (as no extended or logical partitions were needed or possible) equal to my internal memory. I went into the installer and clicked the advanced partitioning a few screens in. At that screen I selected the ext4 partition, clicked add, set it to formatted and be the "/" location in settings. Then I selected the swap, clicked add, an set the option for swap. After which I just moved forward with the install as normal. When finished I rebooted, into the new system and it registered GPT. SUCCESS!!!

Of note, after that I did set up trim support for my specific ssd, as mentioned in the Linux Mint Hardware Compatibility site, and I was good to go.

Special Note: I sure hope next time the automatic Linux Mint installer supports GPT from the get go. I wonder how many people have this problem and don't even know it?? They set up GPT, but never check after install to see it is actually set up right.

[xenopeek]

Thanks for sharing the solution and the steps used

I haven't yet found if the Ubiquity installer for Ubuntu 12.04 will support GPT... That one will probably be used for Linux Mint 13.

[srs5694]

Actually, my memory of what the Ubuntu installer does is:

• On blank drives under about 1 TiB, it uses MBR
• On blank drives over about 1 TiB, it uses GPT
• On drives with an existing partition table, it uses the existing system

My suspicion is that lotharjade's problem was that the disk originally contained a GPT but no partitions and/or that by selecting an option to use the whole disk, it started over with the "blank drive" rule and created a new partition table.

[lotharjade]

srs5694, you may be right on how things work, but... Linux Mint should be not only clearer on how that works (I had to find out the hard and aggrivating way), but there should be a clearer option for newer users. Just giving (bringing up) the option in the automatic installer (maybe when a different partition table is detected) probably would benefit many. It would be like "Oh! There is a fork in the road, and I should read up on the subject, and make a decision", versus having to figure out without much information (you have to know which questions to be asking. Hard for us noobish types).

From what I read, GPT is kinda where things seem to be going as it offers additional features not found in MBR, and has some added performance/stability benefits (or whatnot). ...At which point does Linux Mint (or Ubuntu) start leaning in that (GPT) direction for most installs?? After reading, I am surprised they have not shifted awhile ago. Hasn't even Micro$oft already started going to GPT with Windows 7 for new installs? I thought Linux usually lead the way with better tech adoption?

[srs5694]

From what I read, GPT is kinda where things seem to be going as it offers additional features not found in MBR, and has some added performance/stability benefits (or whatnot). ...At which point does Linux Mint (or Ubuntu) start leaning in that (GPT) direction for most installs?? After reading, I am surprised they have not shifted awhile ago. Hasn't even Micro$oft already started going to GPT with Windows 7 for new installs? I thought Linux usually lead the way with better tech adoption?

You should not think of GPT as something that should be used by default for most installs. GPT is a useful technology when applied appropriately, but it should not be applied in all cases. To understand why this is so, consider Fedora, which has been pushing GPT in its last release or two. The Fedora forums are filled with posts about problems that have resulted from this overly-aggressive pushing of GPT. Some problems relate to buggy BIOSes that flake out with GPT and others can result when a user wants to install Fedora and then install Windows, since Windows won't install to a GPT disk except on UEFI-based computers.

Overall, something like the Ubuntu policy seems best, although I'd move the cutoff for using GPT up to 2 TiB and I'd give better control of the choice to users in the installer. Using GPT as the default on BIOS-based computers is asking for trouble.

Don't get me wrong, though; GPT is a major step forward over MBR, even on BIOS-based computers. It's just that it's not universally appropriate. Its advantages are relatively small except on disks that are over 2 TiB in size, and although the problems are rare, they're much bigger than its advantages when the problems crop up. This makes switching to GPT desirable only when the user knows what s/he is doing, when the computer uses EFI, or when it's necessary because of disk size issues.