Meddling about with partitions on macbook-please help me backup

Discussion in 'Mac Basics and Help' started by angryhive, Jun 1, 2008.

  1. angryhive macrumors newbie

    Jun 1, 2008
    Hello, i'd like to meddle about with partitions on my friend's macbook. It came with a "macintosh HD" partition and the idiotic "Data disk" that some third party cowboys seem to like creating. Anyway, as i'm sure plenty of people here know, this is not appreciated by bootcamp. So, i'd like to delete the "data disk" partition with diskutil, enlarge the "mac HD" partition, then run bootcamp to install windows etc.

    I'm quite good with computers, but not with macs. My specific worries are the 200mb EFI partition at the start of the disk. What i would like to be able to do is, if i completely screw up, to be able to restore the entire thing so that it's all working okay.

    So, i know i can use superduper(!) to backup an image of "mac HD", so that it can be restored. But what about the EFI partition? Can i back this up? Can i restore it with the osx install disk if i cannot? Is this even necessary? Basically, what steps can i take so that if i were to, say, format the entire drive as empty space or something stupid like that, i could just go "bing!" with the backup, hip hip hoorah, everything works again?

    Any help would be appreciated! (except people telling me to use virtual machines or not to use windows xp at all because the mac osx is so much better anyway, etc. etc. etc.)
  2. italiano40 macrumors 65816


    Oct 7, 2007
    that is what i would do, and for the EFI use Carbon Copy Cloner 3.1
  3. angryhive thread starter macrumors newbie

    Jun 1, 2008
    soo...CCC backs up the ENTIRE disk, rather than just the partition? And the resultant image can just be restored by CCC, and all is well? I have CCC, but haven't used it yet. Can i use it to just image the EFI partition, and have superduper do the rest, then?

    Also, (thanks for helping by the way, i am so in need of someone to talk to about this) if i were to just image "Mac HD" with superduper, and the EFI partition with CCC, i could be back to normal easily enough, correct? Because there's nothing useful on data disk, and restoring only an EFI partition and mac HD partition with no "data disk" partition won't confuse os x, correct?

    Thanks again!
  4. merl1n macrumors 65816


    Mar 30, 2008
    New Jersey, USA
    EFI is firmware, not a partition.

    Since you have SuperDuper and know how to use it, you have no problem. You can easily make a clone of your Macintosh HD to it.

    Now to the partitioning on the Mac...

    Use Disk Utility (/Applications/Utilities/Disk Utility and select the actual device name (not any of the volumes beneath). Go to the Partitions tab.
    Change "Current" to "1 Partition". Now name the disk to anything you want, but do not include any spaces in the name (Unix does not like spaces in names). Click Apply and the disk will reformat correctly. Note that this will completely wipe your disk.

    Now boot from the cloned drive and user SuperDuper to restore your mac using "Macintosh HD" (the clone) as the source and the new partition as your target.

    After the clone is finished, run Disk Utility again (from the clone) and do the following after selecting the new volume:

    1. Repair Permissions
    2. Verify Disk and
    3. Repair Disk (optional, use only if you found errors in step 2)

    That's it.
  5. angryhive thread starter macrumors newbie

    Jun 1, 2008
    Uhh..merl1n, that sounds a bit scary. The way i was going to do it was to make an image of "Mac HD" for backup in case of errors, delete the "data disk" partition, then use diskutility to enlarge the "Mac HD"partition". Would this also wipe all my data? Or would this be nondestructive?

    I suppose i don't really want a blank disk unless i have to have one. I'd get shouted at if i botch up. Is your way (create image, format as single partition, restore image) the "proper" way? Or can i resize the existing partition? Is there more chance of data loss the way i was going to do it?

    Finally, what do you mean "EFI is firmware"? It shows up as a 200mb space of some sort in gparted, FAT i think, so what is it?

  6. merl1n macrumors 65816


    Mar 30, 2008
    New Jersey, USA

    Actually making a clone is a simple process, just a little time consuming that's all. In case you make an error, you could always boot from the clone.

    If you just make an image file, I'm not sure how you could boot from it to restore your system (maybe a Leopard option using the Leopard DVD?).

    Anyway, I do this all the time and keep current clones.

    How would you delete the "data disk"?

    Yes, you can enlarge the Mac HD partition under Leopard and your data "should" be intact on that partition.

    How many partitions do your have?

    You refer to a Mac HD partition, a data disk partition, and now an EFI partition? Or is the data disk partition named EFI?

    EFI is usually referred to the firmware of the mac as in an "EFI firmware update".

    Please explain, I'll be monitoring this thread.
  7. angryhive thread starter macrumors newbie

    Jun 1, 2008
    Uh, yeah, by image i think i meant "bootable hfs partition on an external drive". Sorry if this was unclear :D

    how would i delete data disk? Boot from CD, run diskutil, choose the device, select partition "data disk", click erase.


    I have the following partitions (from memory) (now checked)

    1 200mb "FAT32"(according to gparted) which i assume is this mystical EFI thing

    2 "Macintosh HD" with the operating system on

    3 a very small 128 mb gap which according to gparted contains nothing

    4 "Data disk" which i assume contains nothing useful

    5 another very small 125mb gap

    So, if i create a bootable backup of "Mac HD" on external drive with superduper!, delete (if i can) "data disk" partition, and try and resize the Mac HD, i could always (if it screws up) follow your method from there (format as one partition with diskutil, restore from cloned osx), couldn't i?

    And, you don't seem to be treating the EFI thing with any concern. Should i just forget the 200mb at the start of the disk?

    Thanks again!
  8. merl1n macrumors 65816


    Mar 30, 2008
    New Jersey, USA
    A bootable hfs partition as you describe is just a bootable OS. Same thing as doing a clone of your Mac HD partition using SuperDuper like I suggested.

    No, that just erases the partition (clears the data off of it). It does not get rid of it.

    Ok, I just tried what you want to do on a scratch disk of mine and here is what I found.

    1. Yes you can delete a partition without affecting the other partitions.
    2. The deleted partition must be the one directly underneath the partition you want to enlarge.

    So in essence if you have the following setup:

    Partition1 200mb "FAT"(according to gparted) which i assume is this mystical EFI thing

    Partition2 "Macintosh HD" with the operating system on

    Partition3 a very small 128 mb gap which according to gparted contains nothing

    Partition4 "Data disk" which i assume contains nothing useful

    Partition5 another very small 125mb gap

    If you delete Partition1, you cannot add it to Partition2.
    If you delete Partition3, you CAN add it to Partition2
    If you delete Partition4, you cannot add it to Partition2 unless you delete Partition3 first, grow Partition2 (using ALL of the space from Partition3) and then grow Partition2 (again) with ALL of the space from Partition4.

    So, if Partition1 is indeed the FAT partition, you are screwed.

    Again the safest way of making one partition is the method I told you about, using SuperDuper, in my Post# 4 earlier.

    I would get rid of it and make one big partition (see Post4).
  9. angryhive thread starter macrumors newbie

    Jun 1, 2008
    Right, i think i'll try your method, then, if partitions cannot be merged. Just to be clear though, the 200mb FAT32 whatever thing at the start of the disk is only visible through gparted. It cannot be seen using mac os diskutil. I did see something on ubuntu forums about how it can just be deleted with no ill effects, and also i saw the opinions of an equal and opposite expert who said this isn't such a great idea. I wouldn't have a clue myself.

    I'm pretty sure-ish that just about everyone with a standard mac partitioning scheme has this 200mb thing at the start of the disk if their hard drive is over a certain size or something like that. But i don't think it can be deleted using diskutil, because it can't see it.

    So, diskutil only shows 2 partitions, mac HD and data disk. But if i choose the 1 partition scheme like you said, it should work out okay, i hope?

    Well, i'll give it a go. Can i come back if i get stuck?
  10. merl1n macrumors 65816


    Mar 30, 2008
    New Jersey, USA
    No I don't think so unless Boot Camp puts it there.

    What you should do.

    Make your clone of the Mac HD volume on an external disk. Refer to Post 4.

    Boot from the external disk and run Disk Utility.

    Select the actual drive from the mac and go to Partitions tab.

    Change Current to 1 Partition (this also enables the options button)

    Click the options button and make sure the partition map is set to GUID.

    Click ok

    Name the disk as I suggested before (no spaces).

    Click apply.

    Now the disk is fully formatted.

    Now launch SuperDuper. Set your clone name as the source and your target as the newly named partition.

    When that is done, run Disk Utility again... (see Post 4).

    Now boot from your internal disk.

    If you do it this way, you can't make a mistake.
  11. angryhive thread starter macrumors newbie

    Jun 1, 2008
    Fantastic guide man, i'm going to print it out and stick it on the wall! I shall let you know how it goes.

    Thank you very much!


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