Resizing or "cloning" an existing (Windows 8.1) virtual HD under KVM on OS13.1

English Virtualization
#1

I installed Windows 8.1 as a KVM guest on OS13.1. I had to select “copy host CPU configuration” which filled in the field with “Nehalem”.

After I got it running on an 8Gig virtual disk, I tried to update the software and ran out of disk space. I know I could simply blow it away and start over, but I would like to be able to “fix” the problem.

Is there a way to expand the existing virtual disk (.raw) without breaking the installation? Is it possible to create a new disk and “clone” the existing system to the new disk, and then grow the system partition? I know this is somewhat of a “Windows” question, but I’m asking about the Linux aspects of the problem.

#2

Can’t you just use virt-resize and then expand the drive when you boot to Windows?

You can find the tool by installing the guestfs-tools package.

#3

And before you do anything, please do take backups of all VM files :slight_smile:

#4

Thanks. That got me pointed in the right direction. I found this:
http://libguestfs.org/virt-resize.1.html

And did this:


# virsh list --all
 Id    Name                           State
----------------------------------------------------
 -     win8                             shut off
 -     os13-1-1                       shut off

# virsh dumpxml win8 | xpath /domain/devices/disk/source
Found 2 nodes:
-- NODE --
<source file="/var/lib/libvirt/images/win8.img" />-- NODE --
<source file="/home/hattons/Downloads/com/microsoft/9200.16384.WIN8_RTM.120725-1247_X86FRE_ENTERPRISE_EVAL_EN-US-HRM_CENA_X86FREE_EN-US_DV5.ISO" />

# mkdir virt-temp

# cd virt-temp

# truncate -s 40G outdisk

# virt-filesystems --long --parts --blkdevs -h -a /var/lib/libvirt/images/win8.img
Name       Type       MBR  Size  Parent
/dev/sda1  partition  07   350M  /dev/sda
/dev/sda2  partition  07   7.7G  /dev/sda
/dev/sda   device     -    8.0G  -

# virt-resize --expand /dev/sda2 /var/lib/libvirt/images/win8.img outdisk
# virt-resize --expand /dev/sda2 /var/lib/libvirt/images/win8.img-8G outdisk
Examining /var/lib/libvirt/images/win8.img ...
**********

Summary of changes:

/dev/sda1: This partition will be left alone.

/dev/sda2: This partition will be resized from 7.7G to 39.7G.  The 
    filesystem ntfs on /dev/sda2 will be expanded using the 
    'ntfsresize' method.

**********
Setting up initial partition table on outdisk ...
Copying /dev/sda1 ...
 100% 
Copying /dev/sda2 ...
 100% 
Expanding /dev/sda2 using the 'ntfsresize' method ...

Resize operation completed with no errors.  Before deleting the old 
disk, carefully check that the resized disk boots and works correctly.

# mv /var/lib/libvirt/images/win8.img /var/lib/libvirt/images/win8.img-8G

# mv outdisk /var/lib/libvirt/images/win8.img

# virt-filesystems --long --parts --blkdevs -h -a /var/lib/libvirt/images/win8.img
Name       Type       MBR  Size  Parent
/dev/sda1  partition  07   350M  /dev/sda
/dev/sda2  partition  07   40G   /dev/sda
/dev/sda   device     -    40G   -

My Win8 guest now has enough drive space for the time being.

Thanks