jake10e

Q: Disk Utility defaulted to Logical Volume Group format for new 4TB HDD and won't let me change to GUID. Is that a problem?

I just installed a 4TB HGST HDD in the 4th bay of my mid-2010 mac pro (2.8 GHz Quad-Core Intel). I formatted the drive using Disk Utility's "Erase" tab as Mac OS Extended Journaled and the drive seems to be working fine (set up as Time Machine backup).  It is recognizing the full 4TB capacity and the first backup in TM took a long time but all the files are there.  However, my understanding is that all drives intended for use solely in my mac should ideally be formatted to GUID.  The problem is that Disk Utility formatted the drive to a Logical Volume Group/Logical Partition, so it's not allowing me to change the format type now i.e. when I go to the "Partition" tab in Disk Utility, all of the options are greyed out.  Also, the RAID tab does not appear for this drive as it does for the other three 1TB drives installed.

 

So my ultimate question is this - is it a problem that I can't reformat to GUID?  If so, why is it a problem and how do I fix it?

 

Thanks!

Mac Pro, OS X Mountain Lion (10.8.4)

Posted on Aug 19, 2013 12:23 AM

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Q: Disk Utility defaulted to Logical Volume Group format for new 4TB HDD and won't let me change to GUID. Is that a problem?

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  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 7, 2013 9:24 AM in response to Alley_Cat
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    Dec 7, 2013 9:24 AM in response to Alley_Cat

    I dunno how you managed to do that.

     

    ¿ Did you simply Partition, rather than Erase?

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 7, 2013 9:29 AM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 7, 2013 9:29 AM in response to Grant Bennet-Alder

    Yes, I would not have erased it.

     

    Have I been doing it wrong all these years

     

    AC

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 7, 2013 9:37 AM in response to Alley_Cat
    Level 9 (61,250 points)
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    Dec 7, 2013 9:37 AM in response to Alley_Cat

    Have I been doing it wrong all these years

     

    ...and now you are the only peron around who has a new large drive that works under 10.8.4 through 10.9.0.

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 7, 2013 9:51 AM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 7, 2013 9:51 AM in response to Grant Bennet-Alder

    It would have been an unformatted drive so I would never have thought to use the erase option.

     

    Basically following:

     

    Screen Shot 2013-12-07 at 17.46.52.png

    from this or similar:

     

    http://manuals.info.apple.com/MANUALS/0/MA173/en_US/MacPro_HardDrive_DIY.pdf

     

    I've always assumed it does some kind of 'quick format' .

     

    AC

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 7, 2013 9:57 AM in response to Alley_Cat
    Level 9 (61,250 points)
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    Dec 7, 2013 9:57 AM in response to Alley_Cat

    ¿ You read the directions ?

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 7, 2013 9:58 AM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 7, 2013 9:58 AM in response to Grant Bennet-Alder

    Probably quite some time ago....

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 7, 2013 11:51 AM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 7, 2013 11:51 AM in response to Grant Bennet-Alder

    Grant Bennet-Alder wrote:

     

    Have I been doing it wrong all these years

    ...and now you are the only peron around who has a new large drive that works under 10.8.4 through 10.9.0.

    Just to see if it's reproducible:

     

    New 4TB WD black added (FW drives and bay 4 removed):

     

    Screen Shot 2013-12-07 at 19.45.33.png

     

    Screen Shot 2013-12-07 at 19.34.10.png

    Screen Shot 2013-12-07 at 19.34.27.png

    Screen Shot 2013-12-07 at 19.34.41.png

    3 partitions 2x320GB and the rest:

    Screen Shot 2013-12-07 at 19.40.29.png

    Screen Shot 2013-12-07 at 19.40.51.png

    Screen Shot 2013-12-07 at 19.42.46.png

    Screen Shot 2013-12-07 at 19.43.25.png

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 7, 2013 12:44 PM in response to Alley_Cat
    Level 9 (61,250 points)
    Desktops
    Dec 7, 2013 12:44 PM in response to Alley_Cat

    So If I hear you correctly, you are saying an additional work-around is:

     

    DO NOT CLICK "ERASE" or your drive will be unusable!

    Use only the "Partition" tab.

    Follow the promts to create the number of partitions desired.

    Done.

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 7, 2013 1:17 PM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 7, 2013 1:17 PM in response to Grant Bennet-Alder

    I think you are suggesting no one does this normally, but yes, for both previously unformatted drives I simply clicked on the drive and Partition rather than Erase in Disk Utility.  I have no idea what would happen with a previously formatted drive but couldn't see any point erasing a new drive whcih most of mine are when I partition  them.

     

    Just wanted to test that I could Partition another new 4TB drive via DiskUtility in 10.8.5.

     

    I don't think I've ever used the Erase option to be honest - I might if I was giving a drive away but once I partition and format a drive I rarely re-partition it or give it away anyway.

     

    Does using Erase perform a low-level format of some kind that would take all day on a large drive?

     

    Tried making a couple of partitions this time just to see it wasn't unique to a single partition option.

     

    Also diskutil cs list still give a 'No CoreStorage logical volume groups found'

     

    AC

  • by The hatter,

    The hatter The hatter Dec 7, 2013 2:09 PM in response to Alley_Cat
    Level 9 (60,935 points)
    Dec 7, 2013 2:09 PM in response to Alley_Cat

    I am more like you.  Use the Partition tab primarily and only lately ever used Erase.

     

    You have to choose "Secure Erase" to write zero to the entire drive, otherwise it is a quick zero, tests all the blocks though where partition tables will be locked into place and insures a backup volume information block exists and works, so the first and last (400,000? more?) sectors are w/o any write/read error.

     

    Interesting that DU behaves differently as I thought some folks had tried at least to partition 4TB into 2 x 2TB to see if they could get around the issue, but never a success story at a 3TB or larger partition.

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 7, 2013 3:34 PM in response to Alley_Cat
    Level 9 (61,250 points)
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    Dec 7, 2013 3:34 PM in response to Alley_Cat

    Does using Erase perform a low-level format of some kind that would take all day on a large drive?

    In the dim distant past, it would indeed re-write the block number headers and all the formatting information. Modern drives often use a mechanical device to discern rotational position, so only the data blocks are re-written when you do the equivalent of "format".

     

    The time required to re-write all the data blocks can easily stretch into hours. That is why skeptical old f@rts like me assume the factory did not take the time to do it properly and insist that "whenever a drive is re-purposed" is an ideal time to re-write everything.

     

    Disk Utility does not erase more than the Directory area when you say Erase with no additonal options selected. To get Disk Utility to do overwrite the entire data area, you have to use Security Erase option, and move it off the default at least one click to get it to write one pass of Zeroes over the entire data area.

  • by Alley_Cat,

    Alley_Cat Alley_Cat Dec 8, 2013 2:45 AM in response to Grant Bennet-Alder
    Level 6 (19,593 points)
    Dec 8, 2013 2:45 AM in response to Grant Bennet-Alder

    Grant Bennet-Alder wrote:

     

    Does using Erase perform a low-level format of some kind that would take all day on a large drive?

    In the dim distant past, it would indeed re-write the block number headers and all the formatting information. Modern drives often use a mechanical device to discern rotational position, so only the data blocks are re-written when you do the equivalent of "format".

     

    The time required to re-write all the data blocks can easily stretch into hours. That is why skeptical old f@rts like me assume the factory did not take the time to do it properly and insist that "whenever a drive is re-purposed" is an ideal time to re-write everything.

     

    Disk Utility does not erase more than the Directory area when you say Erase with no additonal options selected. To get Disk Utility to do overwrite the entire data area, you have to use Security Erase option, and move it off the default at least one click to get it to write one pass of Zeroes over the entire data area.

    Thanks for the explanation. On Windows formatting used to take an eternity unless you used a quick format technique, though I always used to use the slower option.  SInce moving to Macs in 2006 and with drive sizes increasing significantly I have always assumed teh partition option just did a quick format/partitioning and never really looked for teh full format which I assumed would take many hours or even days to complete on drives over 1TB.

     

    Seems this technique does currently work in 10.8.5 for drivesover 2TB using Partition - I wonder if the supplemental update a few weeks ago added a fix quietly?

  • by Frank Lowney,

    Frank Lowney Frank Lowney Dec 14, 2013 11:59 AM in response to Frank Lowney
    Level 1 (113 points)
    Dec 14, 2013 11:59 AM in response to Frank Lowney

    Here's the solution that worked for me.  I booted into MacOS X 10.7 from an external disk, launched Disk Utility from there and noticed right away that disks that were seen as Logical Volume Groups under 10.9 were seen as GUID volumes under MacOS X 10.7.  The names of the disks were correct and everything looked as I would have expected. Even the disk names were back to their originals. They had been changed to the name of one of the partitions when I erased the partition and changed that name under 10.9.

    So I used Disk Utility under 7.0 to erase and re-partition one of the disks.  These options were not available in Disk Utility under 10.9.

     

    Rebooting into 10.9, I note that Disk Utility there shows this disk and its partition as GUID so that seems to be a way to recover from this situation. 

     

    I am currently in the process  of carefully shuffling data around so that I can erase a re-partition the other affected volumes.

     

    To speculate, I would  guess that Apple changed Disk Utility to accommodate fusion disks and, in doing so, screwed things up. I have logged a report of this at bugreport.apple.com.

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Dec 14, 2013 12:14 PM in response to Frank Lowney
    Level 9 (61,250 points)
    Desktops
    Dec 14, 2013 12:14 PM in response to Frank Lowney

    To speculate, I would  guess that Apple changed Disk Utility to accommodate fusion disks and, in doing so, screwed things up.

    There is anecdotal evidence that this was caused by an attempt to accommodate WINDOWS drives over 2.2TB.

     

    Also, the labs at Apple may be populated with black cylindrical Mac Pro prototypes, so there may have been few opportunities to test Internal Drive issues. External Drives work fine.

  • by macsantos,

    macsantos macsantos Jan 20, 2014 12:47 PM in response to jake10e
    Level 1 (0 points)
    Jan 20, 2014 12:47 PM in response to jake10e

    SOLUTION:

     


    I have experienced the same problem that others have here. I have an Intel MacPro in which I recently installed a new internal 3TB hard disk.

     

     

    I attempted to format it in Disk Utility under OS X Mountain Lion (10.8) using standard GUID partitioning. But disk Utility formatted it using a Logical Volume Group (LVG) instead of GUID.

     

    Disk Utility subsequently refused to allow me to reformat or repartition this drive. Ithought I was stuck with a LVG drive.

     

    For the solution that worked for me see the answer by GrowlTiger at AskDifferent

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