How to move free space from one partition to another?

Discussion in 'macOS' started by qwimjim, Jan 20, 2011.

  1. qwimjim macrumors regular

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    #1
    I have my drive split in two partitions, I want to take excess free space from my main "System" drive and move it to my "Data" drive where I keep all my personal and media files. I went into the disk utility, and shrunk the System drive by 25Gb, and now I (visually) have this dead space between the two partitions. But I can't move the Data partition up so that I can enlarge it by pulling the resize tab in the bottom right. Not sure what to do, it seems my only option is to re-allocate that free space back to the system drive.
     
  2. mjsmke macrumors 6502a

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    #2
    I dont think you can without formatting the drive. Though you could add a partion in that free 25GB.
     
  3. MacTech68 macrumors 68000

    MacTech68

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    #3
    Cloning your drive, erasing and repartitioning and restoring your FULL backup is probably the best way to go.

    However, it's not impossible, ProsoftEngineering's Drive Genius can do this on the fly, but I would still recommend the full backup/erase/repartition/restore method.
     
  4. qwimjim thread starter macrumors regular

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    #4
    Well coming from a PC I have to say that's INSANE. It's such a trivial matter to move free space from one partition to another on a PC, and you guys are telling me it's not possible on a Mac where everything else is simple?

    That really sucks
     
  5. aussiedj macrumors regular

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    #5
    Terminal

    diskutil list (will give you your drive listings & their paths)

    diskutil resizeVolume

    Obviously you cannot create a new partition with the left over space & expect to join 2 created partitions, you will need to have that free space FREE, unless you want to fork out $50 for iPartition (which is well worth the money & has saved me a few times when dealing with NTFS drives)
     
  6. MacTech68, Jan 20, 2011
    Last edited: Jan 20, 2011

    MacTech68 macrumors 68000

    MacTech68

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    #6
    Perhaps I've spoken too soon, according to this, it's possible:

    http://support.apple.com/kb/HT2374

    I've not done this before (I don't use partitioned drives except on my home server) so can't offer any tips. Nor does the above article show specifically how it's performed.

    Anybody else?

    EDIT: seems you can only reclaim space from a partition that is logically before another. One of the two you resize will be erased. I would prefer to experiment with this WELL BEFORE implementing it and as always, backup first!

    To be fair, I've never liked the idea of resizing a live/active partition.

    EDIT 2: Seems the only thing you can do (without iPartition etc) is to change the END POINT of a partition. DiskUtility and the disktuil resizevolume can NOT change the start point of a partition.

    EDIT 3: Finally, this post on Apple Discussion forum really sums it up.
     
  7. aussiedj macrumors regular

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    #7
    OK, none of you are thinking outside the box at all.

    First of all, why would you partition your drive in the first place to separate "OS" and "DATA"?? That just makes NO SENSE! Unless of coarse you are running windows on the other partition.

    If that was the case, you could just merge them all together with iPartition, or with the terminal command as stated above, and then FOOLISHLY split them up again for absolutely no reason other than to be in this same situation again in 3 months.
     
  8. qwimjim thread starter macrumors regular

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    #8
    I have always done things this way and it works quite well, though usually I have two separate drives vs one partitioned drive. I much rather have all my personal files completely separate from system/application files.

    The only reason I am in this position is because I overestimated how much room I would need for OSX and applications by about 25Gb. But it's pretty incredible that a basic feature that was available in Windows 20 years ago still hasn't made its way to OSX.
     
  9. MacTech68 macrumors 68000

    MacTech68

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    #9
    I'm glad somebody said it. :eek:

    Like I said, I only use it on my home server.

    Added to aussiedj's comment, minimizing the boot partition's size also reduces the available contiguous space for VM storage, potentially slowing the performance of your machine.

    However, partitioning IS the end user's choice. :cool:

    To be fair to the OP, the question was "how to do it" not "should I or shouldn't I". :)
     
  10. MacTech68 macrumors 68000

    MacTech68

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    #10
    Both OSs have their shortcomings.

    And as I already stated, reducing the free contiguous space on your boot partition will mean Virtual Memory (when required) will more likely be fragmented all over that partition as it competes for space.
     
  11. r0k macrumors 68040

    r0k

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    #11
    No it was not. 20 years ago and 10 years ago you needed third party software to resize partitions on Windows. The one I used was partition magic.

    You do know about sym links, right? Take one of your bigger apps and move it to another volume. Then in terminal do the following:

    cd /Applications
    lin -s /newvolume/apps/Appname.app Appname.app

    Done. Now OS X thinks the app you have sitting on drive newvolume is actually sitting in /Applications. Sym links are only the tip of the iceberg of how a Unix based OS is superior to Windows in almost every way when it comes to filesystem management. Of course the converse is true. You can copy 25 gig of music or photos to the system volume and sym link to them from your data volume. Still, I have to agree with other posters in this thread who criticize the practice of splitting volumes. Perhaps back in the day when reinstalling Windows meant wiping c: you got in the habit of protecting your data by moving it off to d:. Or perhaps you are suffering from bad FAT 16 or FAT 32 file allocation versus partition size limitation memories. Once you've been through migrating from one Mac to another via firewire or doing an archive and install of OS X, you will realize that any time spent futzing around with partitions is time wasted, (unless you are running bootcamp or parallels).
     
  12. aussiedj macrumors regular

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    #12
    So, I have now told you twice how to do it using the command line. What's the issue?

    And you are off your head for wanting to keep everything seperate. If you get hacked, do you seriously think that if a hacker could hack into your computer, that they wouldn't know how to go to the other partition? Or, do you think that if your drive dies, that it's going to effect both partitions regardless? Even if you had 2 seperate drives, how do you know which one us going to die first?

    Now go to terminal and since you have already resized your boot partition, the other will be fairly straight forward.
     
  13. qwimjim thread starter macrumors regular

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    #13
    Ok so old habits die hard, I've been on a Mac for two weeks now and let go of a lot of old habits so why not this one too. And yes it probably stems from having to reinstall Windows so very many times over the years. So I'll just create a Data folder on the main drive and move everything there, it will still all be contained in one space (folder) and I won't be splitting up my available space anymore or messing with partitions. So now, what's the easiest way to do this without moving my 350gb around too many times :)
     
  14. aussiedj macrumors regular

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    #14
    You should then use the command: diskutil mergePartitions

    To make it easier, go to Terminal (Applications, Utilities, Terminal)

    Type in: diskutil list

    Post the results here.

    Then I will try to give you the exact command line for you.
     
  15. aussiedj macrumors regular

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    #15
    OK, so it looks like you will only keep the data on the 1st partition according to the terminal command. So you may want to back the 2nd partition up and then do this.

    Making sure that the first partition is JHFS+
     
  16. MacTech68 macrumors 68000

    MacTech68

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    #16
    Indeed: http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man8/diskutil.8.html

    It's not a non-destructive merge. (pardon the double-negative).

    However, the OP could begin by merging the boot & free, unused 25GB 2nd partition. I'm curious as to how much data actually resides on the "Data" partition.

    Doing all this without a backup just makes me shudder. :eek:
     
  17. qwimjim thread starter macrumors regular

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    #17
    I'm backing up the second partition right now, but what I was hoping for was a way to merge the two partitions without having to lose all the data on my second partition, that would save me from copying all 300+gigs back from the backup drive.

    If there's no way to not lose the data I may as well just delete the second partition in disk utility and then I can expand the first partition to use up all that free space. No need for terminal commands in that case.


    /dev/disk0
    #: TYPE NAME SIZE IDENTIFIER
    0: GUID_partition_scheme *500.1 GB disk0
    1: EFI 209.7 MB disk0s1
    2: Apple_HFS Mac 83.5 GB disk0s2
    3: Apple_HFS Data 416.0 GB disk0s3
     
  18. MacTech68 macrumors 68000

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    #18
    Yup. that all sounds good to me. Do you agree, AussieDJ?

    And yes, copying 300GB twice will be a tad painful, but at least you'll have a current backup ;)
     
  19. aussiedj macrumors regular

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    #19
    Ok, well can you confirm in the standard disk utility that they are both Mac OS Extended (Journaled)

    It will say down the bottom once you click on a partition.

    So according to apple & the information in terminal, it states that only the 1st partition is going to be safe, and it will erase the second. Which is unfortunate because all the stuff you want is on the second.

    I would suggest running time machine on an external so at least you have a backup copy. Even if you can just borrow a drive somewhere for a day.

    If worst came to worst, you would have to fork out $50 for iPartition, but even they state you cannot merge, and to shrink the 2nd one to it's minimum, then grow the first one, transfer as much data as possible, and then delete the 2nd & again grow the 1st.
     
  20. aussiedj macrumors regular

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    #20
    Yeah agreed. That makes sense. And copying and resizing is probably going to take just ask long anyway. This is where the 17" comes in handy with it's expresscard (ie - esata 3gb/s).

    Please make sure that the 1st partition is JHFS+ because some partition scheme's aren't supported in keeping your data with disk utility.
     
  21. qwimjim thread starter macrumors regular

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    #21
    Well I'm halfway through the backup, I'll copy it all back over tonight when I'm in bed :) Not the end of the world. While I have everyones attention

    I have a 17" i5 2.53 MBP, but am thinking of getting my wife a 15" i5 2.53 MBP, if I use CCC to clone/backup my hard drive, would I then be able to pop that backup drive in the new Macbook and everything would work? Or would I have to install everything from scratch because of different components, etc..?

    PS. aussiedj yes everything is Mac OS Extended (Journaled)
     
  22. aussiedj macrumors regular

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    #22
    Not sure, I would have thought it would be ok, but I really don't know.

    Why would you want to do that anyway?

    Not sure if replacing HDD yourself voids warranty for full system, or just the drive itself, due to actually pulling the computer apart.
     
  23. aussiedj macrumors regular

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    #23
    CCC looks like a windows version of Time Machine?
     
  24. balamw Moderator

    balamw

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    #24
    Yes, you can even boot from the clone in a USB/Firewire enclosure by holding Alt/Option at boot. Many of us have done that exact thing many times.

    Usually the HDD is considered user replaceable as is RAM. That's not the case for some Macs (like the Mini, MBA).

    I wish I could have CCC on Windows.

    B
     
  25. MacTech68, Jan 20, 2011
    Last edited: Jan 20, 2011

    MacTech68 macrumors 68000

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    #25
    The 17" Core i5 2.53 MBP & the 15" 2.4GHz or 2.53GHz Intel Core i5 MBP are both "Mid 2010" MacBook Pros. If we look at the build versions that shipped with these two models, we find they have both shipped with the same Build numbers (10D2063a, 10D2094, 10D2101a, 10F2108) starting with 10.6.3 Build 10D2063a.

    My conclusion would be that a direct clone onto a new Mid 2010 15" MBP will boot fine. Just use the Combo 10.6.6 Update to bring it up to date if required, even it it ships with 10.6.5.

    This is one of the joys of OSX. :)

    If models are far removed, you can even erase the HD of the new Mac, clone your old OS to the new Mac (must be Intel CPU to Intel CPU OR PPC CPU to PPC CPU), then Boot the new machine with the bundled disks and the MacOS install will offer to "Upgrade" the OS.

    In your case, however, a straight clone between the two models you suggest should work fine.

    EDIT: Yes, migration assistant works too and most things are brought over, but not everything.

    EDIT 2: Also, if you're upgrading the stock 320GB for a 500GB on the 15", see page 37 in the User Guide.

    Also note that the Mac can act like an external FireWire drive by starting it up in "Target Disk Mode". When you boot up the other Mac, the first Mac's Hard Disk will mount on the desktop like a USB or FireWire hard drive allowing you to erase and clone to it.
     

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