http://forums.gentoo.org/viewtopic-t-908100-start-0.html 

i have been using VirtualBox for W7 on my Gentoo machine, without any problems for quite some time.

I have given my virtual disk /mnt/w7/Windows_7.vdi a separate partition /dev/hda1 of size 26 GB. Now the size of the virtual disk has grown and I need more disk space. I have installed a new SATA SSD of size 120 GB an mounted it under /mnt/vb_w7/

My intention has been to move the virtual disk to the new SSD. I did the follwing steps to move the virtual disk:

1. cloned the virtual disk to the new location

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代码:

# /opt/bin/VBoxManage clonehd /mnt/w7/Windows_7.vdi /mnt/vb_w7/Windows_7.vdi 0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100% Clone hard disk created in format 'VDI'. UUID: 0c0f2877-96e9-4455-8629-58957d70ee23

2. Released the old virtual disk, through the VB GUI

代码:

Menu -> Virtual Media Manager -> Right Click -> Release

3. Choose the new location of the (cloned) virtual disk, through the VB GUI

代码:

Settings -> Storage -> Click on SATA Controller -> Right Click and Add Hard Disk -> Choose Existing disk -> brows to the new virtual disk location/mnt/vb_w7/Windows_7.vdi) -> Open

Here I get an error message from VirtualBox:

引用:

"Failed to open the hard disk /mnt/vb_w7/Windows_7.vdi The medium '/mnt/vb_w7/Windows_7.vdi' can't be used as requested device type. Details: Result Code: NS_ERROR_FAILURE (0x80004005) Component: Medium Interface: IMedium {9edda847-1279-4b0a-9af7-9d66251ccc18} Callee: IVirtualBox {d2de270c-1d4b-4c9e-843f-bbb9b47269ff}

I have done the steps according to the VB Manual. I have unfortunately no clue how to solve this.

When I examine the original virtual disk (/mnt/w7/Windows_7.vdi) and the cloned one (/mnt/vb_w7/Windows_7.vdi) the cloned one seems OK with the VBoxManage tool:

代码:

phils_pc philip # /opt/bin/VBoxManage showhdinfo /mnt/w7/Windows_7.vdi UUID:         5fce96ff-44d9-485d-93b1-c6d873a6ef90 Accessible:      yes Logical size:     20480 MBytes Current size on disk: 20480 MBytes Type:         normal (base) Storage format:    VDI Format variant:    fixed default Location:       /mnt/w7/Windows_7.vdi

and

代码:

phils_pc philip # /opt/bin/VBoxManage showhdinfo /mnt/vb_w7/Windows_7.vdi UUID:         0c0f2877-96e9-4455-8629-58957d70ee23 Accessible:      yes Logical size:     20480 MBytes Current size on disk: 19668 MBytes Type:         normal (base) Storage format:    VDI Format variant:    dynamic default Location:       /mnt/vb_w7/Windows_7.vdi

S O L V E D:

The problem was that the permissions for the virtual disk file was changed when cloning the disk.

Here are the complete sequence, in 6 steps, for a successful change of location for the virtual machine files and the virtual disk:

Original location /mnt/w7 (on /dev/hda1) and destination /mnt/vb_w7/ (on /dev/sda1)

Step 1:
Use the VBoxManage tool to clone the virtual disk in order to provide it a new UUID. Give the cloned disk a new name in the same step

代码:

/opt/bin/VBoxManage clonehd /mnt/w7/Windows_7.vdi /mnt/vb_w7/Win_7.vdi

Just copy the file to the new location does not work, because VirtualBox needs a unique UUID for the virtual disk file.
New UUID is: 14a33a14-cac3-4e5b-ae13-72f33be7181b

Step 2:
Modify the permission right to the file (virtual disk)

代码:

# chmod 777 /mnt/vb_w7/Win_7.vdi

in order for VirtualBox to recognize the file as a disk

Step 3:
Expand the capacity of the virtual disk to 100 GB (102400 MB)

代码:

# cp /mnt/w7/Windows 7/ /mnt/vb_w7/

Step 4:
Re-configure the virtual machine (named Window 7) to point to the new directory and to attach the cloned disk
In the VirtualBox GUI:

代码:

Menu -> Virtual Media Manager -> Right Click -> Release

and 

代码:

Settings -> Storage -> Click on SATA Controller -> Right Click and Add Hard Disk -> Choose Existing disk -> brows to the new virtual disk location/mnt/vb_w7/Win_7.vdi) -> Open

Step 5:
Re-configure the virtual machin (named “Windows 7” in my case) to point to the new directory for the snapshots

代码:

General → Advanced → Snapshot folder → “/mnt/vb_w7/Windows 7”

A final check of the virtual disk size:

代码:

# /opt/bin/VBoxManage showhdinfo /mnt/vb_w7/Win_7.vdi UUID:         14a33a14-cac3-4e5b-ae13-72f33be7181b Accessible:      yes Logical size:     102400 MBytes Current size on disk: 19669 MBytes Type:         normal (base) Storage format:    VDI Format variant:    dynamic default Location:       /mnt/vb_w7/Win_7.vdi

Step 6:
Extend the hard disk space in W7

Start the virtual machine to boot into Windows 7 on the newly attached VDI. 

代码:

Go to Start–>Control Panel–>Administrative Tools–>Computer Management In Computer Management–>Disk Management, choose your system drive(Boot), right click on it and choose "Extend Volume"

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文章名称：虚拟机磁盘移动位置后失效解决办法-创新互联
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