1 2 Previous Next 17 Replies Latest reply: Feb 7, 2013 9:54 AM by mynameismyname
mynameismyname Level 1 Level 1 (5 points)

I have a new 27" iMac and am interested in creating an external bootable disk, mainly so I can perform certain maintenace on my HD, like DiskWarrior that can't repair the start-up disk.

 

Per the local Apple's store genius' advice and instructions, I bought a 32GB flash drive (a PNY compact model that was on sale). I formatted it, created 2 partitions so to create also the Recovery Partition, all according to the instructions.  It took about 4 housr to install the system, which was predictable.

 

Trying to boot up from that flash drive --- it took about an HOUR to even show the desktop, and even then, my int. HD would not show up mounted, only my patitioned ext. drive.

 

So first, CAN I AT ALL USE A FLASH DRIVE AS A BOOTABLE DISK?

 

If not, how can I use my ext. drive for that?  It's 1TB size, and already divided to 3 partitioned. MY QUESTIONS ARE:

 

--- Can I use DiskUtility to CHANGE THE SIZE OF AN EXISTING PARTITION, MAKE IT SMALLER? (There's no need for more than about 20GB for a startup disk)

 

--- CAN I ERASE/REFORMAT ONE PARTITION, vs. the whole drive?

 

Thanks so much....


iMac, OS X Mountain Lion (10.8.2), 27", 8 GB Ram
  • 1. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    So first, CAN I AT ALL USE A FLASH DRIVE AS A BOOTABLE DISK?

    Yes, but flash drives are incredibly slow compared to any hard drive.

    If not, how can I use my ext. drive for that?  It's 1TB size, and already divided to 3 partitioned. MY QUESTIONS ARE:

     

    --- Can I use DiskUtility to CHANGE THE SIZE OF AN EXISTING PARTITION, MAKE IT SMALLER? (There's no need for more than about 20GB for a startup disk)

     

    --- CAN I ERASE/REFORMAT ONE PARTITION, vs. the whole drive?

    Yes, to all of the above. Easiest thing to do is use Disk Utility to remove/change the size of the existing partitions. You can also of course erase and repartition, especially if there's nothing on it right now, or only a small amount of data you can temporarily copy to they main drive, and then copy back.

     

    Disk Utility can clone a drive. You can also use Carbon Copy Cloner or SuperDuper!.

  • 2. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    As to the Flash drive, does it make sense for it to take an HOUR to show the desktop? And what could be the reason my int. HD did not mount?

     

    As to the ext. drive, so you're saying I can play with the partitions' size and reformat one single partition, right?

     

    I still prefer to use the Recovery Partition of my new iMac to create the startup disk (partition)....

  • 3. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    As to the Flash drive, does it make sense for it to take an HOUR to show the desktop? And what could be the reason my int. HD did not mount?

    An hour is excessive. I couldn't guess why it would take that long. The hard drive most definitely should have shown up on the desktop. When booted to the flash drive, check the desktop prefs and make sure the option to show drives are checked.

    As to the ext. drive, so you're saying I can play with the partitions' size and reformat one single partition, right?

    It may be a bit more complicated than that, depending on how you want the partitions to be resized. But again, as long as there's currently nothing on the drive, are a small enough amount to temporarily place somewhere else, it would be easier to repartition it with Disk Utility by creating all new partitions.

    I still prefer to use the Recovery Partition of my new iMac to create the startup disk (partition)....

    Either would work for recovery, but the point of cloning a drive is the ability to clone it back; third party software and all in the last state you last backed up the drive. Then you don't have to install the OS, then your software, then your data, or doing a Time Machine linked restore while installing the OS. Much, much faster to just clone a recent backup back to the main drive.

     

    Also, you can't run any third party apps from a Recovery Command+R boot. You can do the minimal choices available from that screen. In order to use DiskWarrior or other app, you must boot to another fully capable drive.

  • 4. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    OK, here is the situation:

     

    I have 3 partitions.  1 is now empty.  The 2nd I can allow myself to erase (that was the mirror of my old Mac), and the 3rd has all my back up files, both an old Retrospect back-up catalog and storage file, and my Time Machine backup folders. All those take total 425 GB space on the 3rd drive, but those REAL backup files (Retrospect, that I would need in the future), are only 150 GB.

     

    I could dump the Time Machine files (going back only a week back), and move the old Retrospect back-up files (those 150 GB) to my int. HD temporarily.

     

    Then I can reformat the ext. drive, repartition it to 2 partitions, and as you suggest, clone my int. HD in one prtition, and copy back the back-up files, and dedicate the 2nd partition for back up only (both my old, and new incremental Retrospect and Time Machine).

     

    Is that a viable plan?

     

    Question:  Can I later change the proportion between the 2 partitions, namely reduce one, so I can enlarge the other (as long as there is free space in the one I want to reduce)?

     

    Thanks...

  • 5. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    As long as what's on the current TM backup isn't important, yes, you can just erase it. Your main boot drive will simply ask you to designate a new drive. Which you can do after repartitioning.

     

    The Retrospect data can easily be dumped into a folder on the main drive as a place to save it while doing the repartitioning. Just copy it back when done. Retrospect may need the new partition to have the same name as it is now in order to locate the data when you copy it back.

    Then I can reformat the ext. drive, repartition it to 2 partitions, and as you suggest, clone my int. HD in one partition, and copy back the back-up files, and dedicate the 2nd partition for back up only (both my old, and new incremental Retrospect and Time Machine).

    I'm not sure about the second part since I never use TM. I don't know how happy it would be about having the Retrospect data on the same partition. You'll want to wait and see of others have advice on that.

    Question:  Can I later change the proportion between the 2 partitions, namely reduce one, so I can enlarge the other (as long as there is free space in the one I want to reduce)?

    Yes. You open Disk Utility and drag the lower corner of either current partition up to make a blank space on the drive. Then click the + button to fill the space with a new partition. The partition you're stealing space from of course can't be so full that you can't modify it.

  • 6. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    I'm not sure about the second part since I never use TM. I don't know how happy it would be about having the Retrospect data on the same partition.

    They're already sharing the same partition, and w/o any issues.  I'm talking about my OLD Retrospect catalog and data (from my old Mac, which I will keep separate, I don't want any new backups to be ADDED to the old file). Since this is a new machine, I still didn't set up Retrospect to nightly back up, so once I set my drives/partitions -- then I will set up Retrospect.

     

    You open Disk Utility and drag the lower corner of either current partition up to make a blank space on the drive. Then click the + button to fill the space with a new partition.

    Wait, but that would create a THIRD partition, no?  I simply want to have the option to later give partition 1 more space -- on the account of partition 2.

  • 7. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    Wait, but that would create a THIRD partition, no?  I simply want to have the option to later give partition 1 more space -- on the account of partition 2.

    Oh! Sorry. It can be done, but it does require removing the second partition and redoing it. Like this example.

     

    Screen shot 2013-02-06 at 1.33.39 PM.png

     

    Here I moved the grab corner at the lower right of the upper partition to make a blank area. I an now press the + button to create a third partition. What you can't do in such a case is grab the top of the lower partition and move it up to fill the space. It's initial position on the drive is locked. So what you'd have to do is backup whatever data is on the lower partition, delete it in Disk Utility (in the work space shown above), shrink the upper partition and then press the + button to fill the now fully blank area below it with a new second partition. Then restore your data.

  • 8. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    OK, so one can reduce the size of a pertition, but not enlarge it. Got it.  In my case, I better calculate carefully what size should each partition be, before partitioning the drive....

  • 9. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    OK, so I started erasing the ext. disk (with its 3 partitions), 2 of them are gone from my Desktop, and the only icon on my desktop is the 1st partition (which is the mirror of my previous Mac), still untouched (I can see all the files, and I can launch programs from there). I got the follwoing message:

     

    Screen Shot 2013-02-06 at 2.59.02 PM.png

  • 10. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    Can't say I've ever seen that one before. How did you go about trying to redo the partitions? It has to be done by launching Disk Utility and choosing the physical drive you want to modify, such as below.

     

    drives.jpg

     

    Did you remove or resize a partition with Disk Utility and then try to erase the remaining second partition with the unused area still blank, or not updated? If so, that would cause an error. You must complete any partition changes you want and click Apply at the lower right of DU so the drive's new setup is complete. Then you can erase the new partitions. Though as long you set the new partition(s) as Mac OS Extended (the default), it's unnecessary since they're already blank.

  • 11. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)

    I actually solved it... I'm reformatting the whole ext. HD, not just a partition.... The Mac, for whatever reason was claiming that some program is running from that ext. drive, and I couldn't even manually drag it's icon to the trash to unmount it... So I just clicked the "force unmount" it, disconnected it, reconnected, and then it would allow me to reformat the drive, and then repartition it.

     

    BUT, I couldn't use DiskUt to "restore" the OS, it said I must restart from the Recovery Partition (restart with Command-R), run DiskUt from there and do the job... I think this is a new, Lion thing...

     

    I now see how it took me over 4 hours last night to load the OS on the Flash Drive, this one, loading it on my FireWire-Thunderbolt ext. drive is already taking couple hours, and still only halfway thru...

  • 12. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    The Mac, for whatever reason was claiming that some program is running from that ext. drive, and I couldn't even manually drag it's icon to the trash to unmount it

    Oh, that's why. Even with no apps open, OS X will occasionally believe something is still using a drive. The correct way to release it is to restart.

    BUT, I couldn't use DiskUt to "restore" the OS, it said I must restart from the Recovery Partition (restart with Command-R), run DiskUt from there and do the job... I think this is a new, Lion thing...

    No, you should have been able to reformat and repartition the external from the main drive. That likely came back to force dismounting it. The OS still believed something was using files on the drive once it was mounted again, so still refused to allow you to use Disk Utility on it.

     

    Ah, well. You've got it done the way you want now.

  • 13. Re: Creating a bootable clone
    mynameismyname Level 1 Level 1 (5 points)
    The correct way to release it is to restart.

     

    I did restart, and it still claimed the same thing... So I had to "force unmount" it.

     

     

    No, you should have been able to reformat and repartition the external from the main drive.

     

    Which I did. The part that would not work thru DiskUt launched from the HD -- was the Restore function, the Mac told me I need to do that by restarting holding the Command-R to start up from the Recovery Partition.

     

    OK, now, my boot disk partition on the ext. drive is named the SAME NAME as my HD.  So that I can destinguish between the 2 drives (like when doing a Spotlight) can I just highlight the mirrored HD name and rename it "Macintosh HD Mirror" or anything like that?

  • 14. Re: Creating a bootable clone
    Kurt Lang Level 7 Level 7 (31,995 points)

    That is just bizarre. I actually can't explain either instance. Restarting should always release any open files since a restart to the computer is the same as starting cold. Nothing has been opened yet.

     

    The only thing I can think of is you may have had a startup item that pointed to an file on the external drive.

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