GPT - GUID Partition Table


  1. Posts : 5
    Windows 7 Ultimate(32-bit)
       #1

    GPT - GUID Partition Table


    Hello,

    I am having a serious problem(atleast for me) with clonezilla, i have downloaded this software around one month back for the purpose of backing up my data as an image so that i can restore it whenever i need. I have cloned 110GB(appr) partition in which 82GB is used from a secondary or spare GPT harddisk(160GB), after that i formatted the drive again as a GPT hard disk i tried to restore the backup image to my spare hard drive, clonezilla is restoring the image but i can't see that restored partition in windows 7 (64-bit). I have tried restoring image two times but the problem is not solved. After restoring the partition second time, i used "Ubuntu 9.04" Live CD just to check whether i can see any thing in ubuntu. And it worked i can see the restored partition & been able to use the data in the restored partitioned. But when I booted to windows 7 it doesn't show the partition. In computer(disk) management the space the restored partition used is displayed as two small 128MB unallocated blocks. When I use cmd->diskpart it showed the partition but as Reserved partiton. Please see the attached images & if any one has some solution for this please let me know as soon as possible as all my data in that partition is now saved as an clonezilla image, i have to restore it in order to use my data.


      My Computer


  2. Posts : 2,736
    ...
       #2

    send2mudunuri said:
    I have cloned 110GB(appr) partition in which 82GB is used from a secondary or spare GPT harddisk(160GB),
    Hello send2mudunuri, and welcome to Windows Seven Forums!

    If I understand correctly, you saved an image of a 110GB partition, 82GB used space. Could you explain what GPT means?

    send2mudunuri said:
    after that i formatted the drive again as a GPT hard disk i tried to restore the backup image to my spare hard drive,

    But the hard drive circled in red here is only 45GB in size, so how does 82GB + fit into a space of only 45GB?

    Please correct my understanding?

    Cheers!
    Robert
      My Computer


  3. Posts : 5
    Windows 7 Ultimate(32-bit)
    Thread Starter
       #3

    iseeuu said:
    If I understand correctly, you saved an image of a 110GB partition, 82GB used space. Could you explain what GPT means?
    what I mean by saying a GPT harddisk is that it is a 'GUID partitioned table'd hard disk not a MBR type harddisk as we commonly use.

    iseeuu said:
    But the hard drive circled in red here is only 45GB in size, so how does 82GB + fit into a space of only 45GB?
    The hard drive is not 45 GB, although i explained it in my earlier post i will explain u again what i have done. The hard disk is a 160GB WD(western digital) SATA harddisk formatted using 'GUID partition table' as two partitions one with around 45 GB & other with around 110 GB. Out of the 110GB i used around 82 GB. I cloned this 110 GB partition & saved as an image(from what i read on the clonezilla website while cloning a partition or a complete harddisk by clonezilla, it doesn't clone complete partition or harddisk instead it clones only the used space but while restoring it restores complete partition including free space, so in my case it is a 110GB partition of which 82 GB was used & further more as i saved as an image which is compressed i got around 73 GB of image).

    I formatted this 160GB drive again as or using 'GUID partition table', after which i tried to restore the image(as i said i tried two times restoring the image, first time i tried by creating partitions similar(approximately) in sizes as before formatting & second time i let clonezilla to do the partitioning according to the saved image, but both times same result).

    So, what u see a 45GB size is not complete hard disk size but it is a result of windows 7 not being able to recognize the restored partition(110 GB) & being able to see the uncloned partition(45 GB). If u see the image clearly u can see one 45GB partition & also two 128MB unallocated spaces[which should be the restored(110GB) partition]. As i said while i use ubuntu live cd i can see both partitions(45GB & restored partition 110GB) and been able to use data in the restored patition.

    I hope this detailed explanation gives u the better understanding of my problem, subsequently enables u to give me the correct solution.
      My Computer


  4. Posts : 2,736
    ...
       #4

    send2mudunuri said:
    formatted using 'GUID partition table'
    I hope this detailed explanation gives u the better understanding of my problem, subsequently enables u to give me the correct solution.
    The 'GUID partition table' is the source of your problem. GPT is relatively new and not completely supported by Windows. How much research have you done about GPT? What little I did says an EFI based computer is required? Are you using an EFI based computer?

    Here are some of the links I found:

    GUID Partition Table - Wikipedia, the free encyclopedia
    Easily Upgrade Any Hard Drive with Linux
    GPT Partition ? - PCMech Forums
    Is It Possible to Install Windows 7 on a GUID Partition Table Disk?
    Windows and GPT FAQ: Version 1.1

    You are very brave to experiment with such new stuff, especially with your important data. I would suggest to you that you use the MBR based partition table while you do more research about GPT. At least you would have a working computer again?

    Cheers!
    Robert
      My Computer


  5. Posts : 5
    Windows 7 Ultimate(32-bit)
    Thread Starter
       #5

    iseeuu said:
    The 'GUID partition table' is the source of your problem.
    may be yes if u look at it in one way, but the real culprit for my problem is 'gparted' or 'parted' that is used in clonezilla, which 'flag'ed or 'marked' my restored partition as 'msftres' or 'MSR' or 'microsoft reserved' partition. Look at this: ,

    particulalrly read 8th post in that page u would understand what i am saying. This 'msftres' or 'MSR' type of partition is found in GPT harddisks, google for more information. This is how I managed to solve my problem myself.

    After reading quite a few webpages i found that we can change 'msftres' flag to another flag using 'gparted'. As I already mentioned i could see the restored partition in ubuntu 9.04 live cd, i used 'gparted' in that cd & changed 'msftres' flag to boot flag(it is not possible to completely get away without any flag in 'gparted' , if it is possible it would have rectified my problem right away). After I booted into win 7 it showed as 'EFI system partition' & I changed the restored partition from 'EFI system partition' type to 'Basic data partition' type in command prompt like this, in cmd:

    C:\>diskpart

    Microsoft DiskPart version 6.1.7600
    Copyright (C) 1999-2008 Microsoft Corporation.
    On computer: MASTER-PC

    DISKPART> list disk

    Disk ### Status Size Free Dyn Gpt
    -------- ------------- ------- ------- --- ---
    Disk 0 Online 149 GB 0 B
    Disk 1 Online 147 GB 127 MB *

    DISKPART> select disk=1
    (here i selected disk=1 because my restored partition is in disk 1, so replace 1 with the no of ur disk.)

    Disk 1 is now the selected disk.

    DISKPART> list partition
    (displays list of partitions in the selected disk)

    DISKPART> select partition=n
    (where n is the no of partition)

    DISKPART> SET ID=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
    (note:EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 is the ID for Basic data partition, for the list of ID for diff types of partitons just type 'help setid' at the 'DISKPART>' or u can also see the guid's of diff partitions in 'GPT' page in wikipedia.com, under the heading of 'partition type GUID's'. We can't change the id of 'MSR' type of partition directly using this command, this point is confirmed when i tried it & also when i type 'help setid' command at diskpart prompt which displays the type of partitions which we can't change to other type by changing guid. Otherwise I didn't have to use the ubuntu live cd to change the 'msftres' or 'MSR' flag to boot flag.)

    That's it atlast win 7 showed the restored partition i was trying all this for, but i couldn't access it right then as a message poped up saying u don't have permission to access this folder. I restarted the system, & then there is my restored partition & I am able to access it now. See the below image, I circled the partition which I was trying to make it available in win 7.



    You can also solve this problem by using a software called 'gdisk' or 'gpt fdisk' for linux if u have any linux distro installed in ur pc. For more details how to use 'gpt fdisk' please see the links below:
    iseeuu said:
    GPT is not completely supported by Windows.
    Yes I agree

    iseeuu said:
    How much research have you done about GPT? What little I did says an EFI based computer is required?Are you using an EFI based computer?
    Enough to use GPT disks in my pc, and ofcourse I know an EFI based motherboard is needed for complete GPT support. No, i am not, my motherboard is Intel 945GCNL. But it's not the case in every situation, i tell u why?, if u read the article in wikipedia about GUID completely for which u also provided the link, under the OS support of GPT heading, u see the list of OS's & their support or ability to work with GPT, in that list see the Linux line, which tells u that linux can boot GPT harddisks on a normal BIOS based hard disks. So there are OS's that are capable of booting from GPT hdd's on a Bios based pc.

    And if u carefully look at above 'computer(disk) management' image that i posted above, u can see the GPT protective partition of my harddisk in which I am using Windows 7 ultimate RTM(64-bit), otherwise see the below picture in which i circled GPT protective partition at the top as well as at the bottom of the below image, in the bootom the adjacent partitioned to the circled GPT partition is my win 7 partition, i also arrowed it as u can see in the picture.



    So u may ask how it is possible?, as far as my knowledge goes it is possible by Hybrid MBR disks, for complete information on GPT, hybrid mbr's & booting from GPT hard disks please check the following links & the links provided in those pages
    And particularly if u r familiar with Hackintosh(mac os x on pc) u would know this thing. And I use Hackintosh.

    iseeuu said:
    You are very brave to experiment with such new stuff, especially with your important data
    No not at all, because i saved the cloned image in my win 7 harddisk which is working, so if that restoration fails then i can do another time.
    iseeuu said:
    I would suggest to you that you use the MBR based partition table while you do more research about GPT. At least you would have a working computer again?
    No problem man, no need to worry about not having a working computer. I have been using GPT partitioned harddisk for almost one year. And even some thing had gone wrong no worries as that's how u learn the stuff.

    Thank you for ur suggestions, & finally for people who have relatively less knowledge like me about computers, especially about cloning & restoring partitions, disks, i want to suggest that use 'Ghost' software for these purposes as there r no hassles, problems, simple to use & much faster than any cloning software available till now. And if some thing goes wrong u can mount the saved image as .vhd(virtual hard disk image) & use that image by using any virtual softwares and be able to access the data.
      My Computer


  6. Posts : 2,736
    ...
       #6

    send2mudunuri;

    I am pleased you found a solution for yourself. GPT, or something like it, may some day replace MBR as a standard hard drive partition table and more computers may support EFI as well. Obviously you are enjoying your work with GPT and I am happy for you.

    However, this tutorial is about using Clonezilla and was not written with new technology like GPT in mind. Personally, I have little interest in GPT at this time as it's benefits far exceed my needs. MBR is sufficient for the equipment I use.

    That does not take away from the value of the knowledge you have gained with GPT. There have been posts here at Windows Seven Forums asking about GPT. If I may, I would suggest to you to open a new thread in the "Hardware" section and share your experience imaging and restoring GPT partitions. You might even describe how to use "Ghost" to perform these tasks and avoid problems. Windows Seven Forums would appreciate your contribution as there seems to be an increasing interest in this topic.

    Warm regards
    Robert
      My Computer


 

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