Sign in with
Sign up | Sign in
Your question

Do I want GPT vs MBR?

Tags:
Last response: in Windows 7
Share
December 2, 2012 5:12:30 PM

I'm installing Windows 7 64-bit, and the RAID controller is showing the BIOS a single 8TB (virtual) drive. It's actually eight drives in a RAID60, but the BIOS sees just the one big drive.

I have a lot of questions about this.

My mainboard (Gigabyte GA-880GA-UD3H) can do EFI and says that's required for booting for drives > 2.2TB.

EFI is set to "Auto", and Windows installed fine, creating the recovery partition and installing to a small (128gb) MBR partition.

When I went into diskmgmt for the first time, it recommended setting the drive to MBR mode so I did. Now I'm wondering whether I should have.

I've seen that you need UEFI BIOS support for GPT, and I don't know if EFI is the same thing or not.

If I'd selected GPT, what would that have prevented me from doing in the future?

Is it compatible with applications run under XP Mode?

What partitioning software (Macrium? EASUS?) might do the best job of converting partitions?

Parted Magic is hanging on me when booting from a USB, so I can't use that one.

Thanks in advance.

More about : gpt mbr

a b $ Windows 7
December 2, 2012 7:02:48 PM

For >2TB volumes you MUST use GPT
m
0
l
December 2, 2012 7:35:56 PM

ex_bubblehead: "Volume" means drive, partition, or what?
m
0
l
Related resources
December 2, 2012 8:05:45 PM

Quote:
My mainboard (Gigabyte GA-880GA-UD3H) can do EFI and says that's required for booting for drives > 2.2TB.

To create a bootable HDD with OS, you will need a MS OS that supports UEFI and GPT for drives =/> 2.2TB.
Quote:
EFI is set to "Auto", and Windows installed fine, creating the recovery partition and installing to a small (128gb) MBR partition.
When I went into diskmgmt for the first time, it recommended setting the drive to MBR mode so I did. Now I'm wondering whether I should have.

MBR is default however if I understand you correctly, it seems that the OS was installed on a 128GB partition so MBR would be your first choice.
Quote:
I've seen that you need UEFI BIOS support for GPT, and I don't know if EFI is the same thing or not.

Yes - The Unified EFI (UEFI) Specification (previously known as the EFI Specification) defines an interface between an operating system and platform firmware.
Quote:
If I'd selected GPT, what would that have prevented me from doing in the future?

GUID Partition Table (GPT) is the next generation of a hard disk partitioning scheme developed to lift restrictions of the old MBR. Being a part of the Extensible Firmware Interface (EFI) standard proposed by Intel to replace the outdated PC BIOS, it offers a number of crucial benefits:
Up to 128 primary partitions for the Windows implementation (only 4 in MBR);
The maximum allowed partition size is 18 exabytes (only 2 terabytes in MBR);
More reliable thanks to replication and cyclic redundancy check (CRC) protection of the partition table;
A well defined and fully self-identifying partition format (data critical to the platform operation is located in partitions, but not in un-partitioned or hidden sectors as this is the case with MBR)
Quote:
Is it compatible with applications run under XP Mode?

NO, as a matter of fact Windows XP does not support GPT or UEFI.
Quote:
What partitioning software (Macrium? EASUS?) might do the best job of converting partitions?

This question is relative and is solely a personal choice. What you have listed should do the trick however there are many other *free* tools via the intertube.
m
0
l
December 2, 2012 8:22:03 PM

ELMO_2006: So can I use both GPT and MBR on this same 8TB virtual drive (with different partitions) simultaneously?

I would like to run XP Mode applications on MBR drives / partitions if possible, as I have lots of legacy 32-bit software.

Would this work with what the BIOS sees as physically separate drives?

I have a MegaRaid 9260-16i, and I was thinking that maybe I could use some features of that controller to help me accomplish this.
m
0
l
December 3, 2012 8:32:47 PM

lasitter said:
ELMO_2006: So can I use both GPT and MBR on this same 8TB virtual drive (with different partitions) simultaneously?

I would like to run XP Mode applications on MBR drives / partitions if possible, as I have lots of legacy 32-bit software.

Would this work with what the BIOS sees as physically separate drives?

I have a MegaRaid 9260-16i, and I was thinking that maybe I could use some features of that controller to help me accomplish this.



Quote:
So can I use both GPT and MBR on this same 8TB virtual drive (with different partitions) simultaneously?

Please explain when you say 8TB virtual drive?

m
0
l
December 4, 2012 12:41:08 AM

ELMO_2006: Learned a few more things today, but first, to answer your question.

LSI refers to drives it "reflects" to the BIOS as "virtual" drives. I have eight drives in a RAID60 created as a single 8TB drive. Windows sees one drive of 8TB for this particular virtual drive.

I have another 2TB that's not part of any RAID (LSI calls it RAID0 drive) which shows up as a 2nd drive / (virtual drive according to LSI) in Windows drive management software.

I have another set of SSDs which are used by the "CacheCade Pro" software module on the controller and Windows / the BIOS never sees them. Only the MegaRaid Software Manager software / boot-time BIOS setup knows the true nature of all the drives.

Now what I COULD have done, and will likely do to simplify things, is go back and use the RAID controller to "break up" the single big drive into some smaller pieces, with maybe one big chunk for a GPT partition drive and have the rest as MBR drives.

Windows would then see 4-5 drives in total, even though they would all be allocated from the same RAID60 array.

I learned about some complicating factors as far as hardware compatibility with the RAID controller is concerned.

I had originally configured the RAID using the WebBIOS configuration utility -- the one you start by pressing <CTRL><H> when the computer is starting up.

That stopped working, and I think it's unhappy about my swapping the Phenom II 1090T for an FX-8150. Windows installed fine with the new processor, and the Megaraid Storage Manager runs fine within Windows, but the <CTRL><H> has stopped working, and that symptom is one that LSI support is familiar with.

They then referred me back to an incredibly thin compatibility matrix document that listed only one AMD Gigabyte Mainboard and a total of three (3) AMD processors.

The FX 6100 (on the list) had the max number of cores with six, and my Bulldozer has eight.

Lots of support for Intel mainboards and processors, of course.

So I'll see if the processor swap was actually responsible for anything.

About the GPT drives, XP Mode and such, I'm still trying to figure out if just ONE GPT drive anywhere in the system means you can't start / run apps in XP Mode. I've heard about people running XP using GPT loader software to use a GPT drive as if it were MBR.

All confusing stuff for me.

Many thanks for your having responded so far.

m
0
l
December 13, 2012 5:37:57 PM


Quote:
Is it compatible with applications run under XP Mode?

NO, as a matter of fact Windows XP does not support GPT or UEFI.


Just want to add my thanks for your post! Very clear and VERY VERY helpful to this legacy sofware worker--I sure need my XP Mode stuff to work on my new machine... T H A N K S

m
0
l
!