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One Drive Appears as Two


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#1 ebgod

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Posted 24 October 2014 - 07:52 PM

Running: Windows 7 Home Premium x64

 

Summary: 

I have a 3TB Seagate drive in a USB 2.0 enclosure. However, when the drive is powered up, Disk Management shows two physical disks - one at 2048GB and one at 746.5GB. I can use each of these disks normally, they'll format, accept new partitions, etc., but can find no way to tell Windows that they're both actually the same disk.

 

The first disk is identified by Windows as Disk 8 and Device Manager as ST3000DM 001-9YN166 USB Device (as expected)

 

The second disk is identified by Windows as Disk 8 and Device Manager as ST300DM 001-9YN166 LUN1 USB Device. This is the drive that I assume to be "fake". I'm vaguely aware of LUNs, but have only encountered them when working with VMs or clustered storage, never on a desktop and certainly not without Windows Server, which means I'm lacking the tools that I would usually use to manage clustered storage.

 

I supposed I could implement a work-around by creating a spanned volume, but since I just lost an impressive amount of data (see "Further Background"), I'm a little gun-shy of sketchy solutions.

 

Steps Tried Thus Far:

- Deleted the drivers entirely and re-attached the enclosure. Both drives installed as before.

- Used DiskPart to "Clear" the drives (hoping that it would also clear whatever header information is making the two-disk distinction". No joy, now they both just show up as uninitialized.

- Formatted the drives in every way that I could come up with, but as expected since I'm only able to touch one drive at a time, only that drive is affected.

 

Further Background:

The disk used to work perfectly under TrueCrypt, but when they dropped support I (stupidly) switched over to DiskCryptor (since Home Premium doesn't have BitLocker). I had a few file corruptions under DC, so I tried to decrypt the drive before searching for a more stable solution. The decryption failed and I lost 2.3TB (and about 4 years) of data. As part of the decryption process, DC created two drives - one for the encrypted data and one of the data that had already been decrypted.

 

After trying with no success whatsoever to recover the data, I gave up and wiped the drive (after many shots of vodka). However, even after the wipe I'm still left with two drives and thus far haven't found a way to combine them back into a single 3TB drive as it once was. (Though, again, without any of the data. Lesson: don't used DiskCryptor if you like your 1s and 0s.)

 

As always, any suggestions are greatly appreciated.


Edited by hamluis, 05 November 2014 - 10:57 AM.
Moved from Win 7 to Internal Hardware - Hamluis.


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#2 JohnC_21

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Posted 24 October 2014 - 08:06 PM

Hello, and Welcome

 

The reason you are seeing two drives is because an MBR disk has a max capacity of about 2TB. The easiest way to get full capacity is to download Partition Wizard. Delete all partitions on the drive after backing up your data. Initialize the disk as GPT. The create and format a partition on the drive.

 

Partition Wizard also has an option to convert an MBR disk to GPT but I have never used it. If you decide to go that route, backup any data on the drive. Once the conversion is complete you should be able to expand the 2TB partition to the full 3TB.



#3 ebgod

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Posted 24 October 2014 - 08:10 PM

Good thinking, but no joy. They're both already GPT. Though I will download Partition Wizard - maybe it will give me some tools that Disk Management and DiskPart don't.



#4 JohnC_21

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Posted 24 October 2014 - 08:13 PM

I would still try deleting both partitions and re-initialize the disk as GPT. Then create a partition in the unallocated space. It should work.



#5 ebgod

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Posted 24 October 2014 - 09:11 PM

I'm sorry, there seems to have been a communication mix-up. I'm not discussing partitions or mapped drives, I'm talking about physical drives (at least as Windows sees them). I'm well acquainted with working with partitions - these show as two completely different physical hard drives, as if I had two drives in the enclosure, complete with two separate rows in Drive Management (as opposed to a single row with xple partitions) and separate drivers in Device Manager (which is not something you'd see for a single drive with multiple partitions).



#6 JohnC_21

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Posted 24 October 2014 - 09:17 PM

Right. When you open Partition Wizard and look at the layout of the drive what does it show? Does each drive 2TB and 746GB show as a separate partition? If not I would use Partitition Wizard to wipe the disk (zero fill quick) then initialize as GPT. You should then be able to use the full capacity of the drive and Windows will see it as one drive.

 

Edit: Another option would be to convert the GPT disks to MBR. Then wipe the disk and partition.

 

If the conversion does not work then try the following.

 

If Partition Wizard for Windows sees the disk as two drives and you cannot delete them or wipe them to create one disk then download the bootable version of Partition Wizard based on linux. It should see the disk as one device. Then wipe the disk and partition.

 


Edited by JohnC_21, 25 October 2014 - 07:36 AM.


#7 ebgod

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Posted 30 October 2014 - 05:32 PM

Wow, I was pretty sure that booting from the CD would work, but apparently not. Even using an external OS the drive still shows as two disks. I can wipe them both (which was done twice - once from the Windows client and once from the CD - hence the delay in replying) and initialize both to GPT, but that's about it. Just for giggles I swapped out one of my internal drives with the "bad" drive and booted to BackTrack3 via USB and confirmed that even without the enclosure in the way Linux sees two drives. 



#8 Wand3r3r

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Posted 30 October 2014 - 05:38 PM

Some drives have a jumper that can make them appear as two drives.  This was done to address large drives not addressable by windows.  Look up the specs of your drive or look to see if there are jumpers.  Can be in the back or on the bottom when the controller is located.

 

Barring that you may need to do a low level format of the drive before doing any partitioning/formatting.  You would need the Seagate tools to do that.  You should be able to download them from seagates web site.


Edited by Wand3r3r, 30 October 2014 - 05:41 PM.


#9 ebgod

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Posted 30 October 2014 - 05:54 PM

Some drives have a jumper that can make them appear as two drives.  This was done to address large drives not addressable by windows.  Look up the specs of your drive or look to see if there are jumpers.  Can be in the back or on the bottom when the controller is located.

 

Barring that you may need to do a low level format of the drive before doing any partitioning/formatting.  You would need the Seagate tools to do that.  You should be able to download them from seagates web site.

That may have taken me down the right path. There's no jumper in place and the jumper for the drive in question (ST3000DM001) appears to only be used to limit data transfer rates, but it did remind me that SeaTools has some handy features, so I installed it. It's only showing one drive. This could either mean that it's smart enough to see past the formatting oddity OR that it's only seeing the first "drive" - there isn't really any way for me to tell at this point. In any case, I'm doing a full wipe using SeaTools, so if it's the first case it should restore the drive. We'll see... (it'll certainly take a while to wipe - I moved the drive back to the enclosure as I wasn't comfortable operating my machine with the internal raid degraded, so I'm either wiping 2TB or 3TB via USB).



#10 JohnC_21

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Posted 30 October 2014 - 10:04 PM

This is one of the most unusuall things I have ever seen. Don't understand why even linux based partition wizard saw the drive as two drives. If Seatools does not work. I am wondering if the following would work. Convert each GPT disk with Partition Wizard to MBR. Then delete those MBR partitions.

 

If that does not work I would think the linux hdparm command to use the internal erase command of the drive would work.



#11 ebgod

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Posted 01 November 2014 - 09:21 AM

I know exactly what you mean. I've been working IT support for 15 some-odd years and have never run into a drive this stubborn without also seeing evidence of an actual error. If the drive was failing platter tests then I'd completely understand and could RMA the drive, but since there's no test that it won't fail I have to assume the drive itself is fine, there's just something written on it that no OS will see past.

 

After three days of non-stop wiping, SeaTools only wiped the 2.x TB drive, not the smaller drive. I'll try hdparm over the weekend (as we don't run any linux boxes my command skills are a little rusty). If that fails, I'll try imaging the drive using our KACE appliance. It's supposedly capable of overwriting any previously existing drive setup, but I'll believe that when it happens.

 

Thanks again for all the great suggestions so far. I'm really amazed that nothing's worked.



#12 JohnC_21

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Posted 01 November 2014 - 12:56 PM

Take a look at the bootable PartedMagic. It has a HDDerase utility and Gparted, the linux partitioning editor. Latest version is $5

 

You can use the terminal in PartedMagic to run hdparm. In terminal use the fdisk -l command to see your devices. In Gparted you can list the devices in the upper right dropdown box but I wouldn't be surprised if it didn't list the drive as two disks. I am pretty sure the Internal Erase command cannot be done when the drive is attached via USB. Only when attached internally to a SATA port.

 

http://linux.die.net/man/8/hdparm

 

https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase

 

http://tinyapps.org/docs/wipe_drives_hdparm.html

 

Take a look at the --dco-restore command.  If the drive is frozen unplugging the SATA drive and re-attaching will unfreeze it. See the last post in this thread.

 

Good Luck. Keep BC updated. I would really like to know if and how you were able to solve the problem.



#13 ebgod

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Posted 04 November 2014 - 08:10 PM

The strangeness continues, but I think I'm now close enough to full functionality that I'm willing to call it a win and move on with life.

 

I took the drive out of the enclosure and put it in a spare desktop, then imaged it using our Dell KACE 2000 appliance. The first step of the imaging process is to boot to a specialized version of WinPE and format the drive. For reasons that are entirely beyond me (a phrase that will appear a lot in this post), this created a 746.39GB partition for the new install of Windows. I know that we have our images setup to use MBR so I wasn't expecting it to span the full drive, but the MBR limit is 2TB, not 750GB.

 

In any case, once the image was complete I booted to the new native OS and saw that the drive appeared as a single drive with four "partitions" (the reason for the quotes will become apparent in a moment). Partition 1 was the small recovery partition that's just part of the imaging process, partition 2 was the 750GB Windows drive, and then TWO "unallocated" partitions side-by-side which shouldn't be possible in Windows - "free" space should be lumped together.

 

I then put a 2nd Windows-equipped drive into the desktop to see how the troubled drive would react as a non-system disk and the drive appeared exactly as it did in the paragraph above - 4 total partitions. I deleted all the partitions, converted the disk to GPT, and re-created my single-partition structure that existed before all this nonsense started.

 

Finally, I pulled the drive out of the donor desktop, put it back in the enclosure and re-attached it to my primary machine. This is where things get really weird... for reasons that are entirely beyond me (told you that would come up again) it STILL shows up as two physical drives, but this time I have disk 10 at 2794.39GB (the full capacity of the drive) with the single partition I created earlier and a SECOND physical disk at 746.39GB that is entirely unallocated space.

 

From where I sit now, I think I'm safe to continue to use the drive as-is, using only the first "drive" and leaving the second "drive" alone (as using that would clearly corrupt the entire thing), so I'm calling the problem technically solved, but it'll be months before I stop scratching my head about where this second drive is coming from and precisely where Windows thinks that 750GB resides.

 

Thanks to JohnC_21 and Wand3r3r for the great suggestions - I wouldn't have made my way to the eventual fix without those trial-and-error shots.

 

Now I'm going to setup an automated backup plan for the drive in case my assumption about safely using the dual-drive setup proves to be incorrect. I'm also going to start as large and information campaign advising against the use of DiskCryptor as I can possibly muster. :P



#14 ebgod

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Posted 11 November 2014 - 09:28 PM

Another update for the sake of completeness. My computer suffered a complete OS breakdown (unrelated to this issue), so I ended up starting again from scratch, including replacing the drive we've been discussing with a spare.

 

This is what will break your minds: new drive, new OS installation, but same exact symptom. I see the full 3TB as one drive and 750GB of "unassigned" space in a separate disk. Still not a problem since I retain full use of the drive, but I just can't wrap my mind around how a symptom can persist through replacement of everything except the system board and enclosure. This ones going down in the record books.



#15 JohnC_21

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Posted 11 November 2014 - 09:50 PM

Looks like you aren't the only one. A person here got 2 3TB drives! I wonder if it is somehow BIOS related?


Edited by JohnC_21, 11 November 2014 - 09:51 PM.





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