Let's say you have a VM file that uses 200G of dynamic space, but really only has 40G in usage. If you add fles and delete, at some point the file will be larger than the current space you are using.
Take this image which shows is using 71G of space on the host:
The actual space being used inside the image is about 43G as we can see:........
For a lot of reasons, it may be convenient to detach or attach live disks to a running VM without having to reboot it. Sure, you can use some network based storage, but when performance counts, attaching a new virtual disk will usually give you better throughput and lower latency in a quick testing situation.
This doesn't work, why not?
drive_add 0 if=virtio,file=/tmp/vm.qcow2,if=virtio,format=qcow2,id=rtt
Interestingly enough Windows 2000 works fine on QEMU 64-bit but you have to specify Pentium as your CPU otherwise it doesn't complete the install (it will not pass the detecting/setting up devices phase).
-vga cirrus is wise because it is supported by Windows 2000 and allows higher resolutions and 24-bit color.
-cpu Pentium emulates an old computer and is necessary for install to complete
-device rtl8139 is important as this oldschool Realtek 8139 NIC is supported by W........
qemu-img can convert many formats.
Here is an example of how to convert different images to different formats for QEMU-KVM
The example above converts a raw windows2019.img file from QEMU to a Virtualbox .vdi
qemu-img convert -f raw -Ovdi windows2019.img windows2019.vdi
-f raw = this means the format of the source image (instead of raw it could be vdi, vmdi, qcow2 etc..)........
This is caused because the user is running as qemu for virt-resize and if qemu does not have privileges to read from the source and write to the destination, it will fail with the below. So either change the uid of qemu or change the ownership of the source and target.
virt-resize --expand /dev/sda2 /root/kvmtemplates/windows2019-eval-template.img /root/kvmguests/kvmkvmuser4515........
What you need to do if you have taken a dd or real raw image dump of a hard disk:
VBoxManage convertdd windows2019-eval-template.img windows2019.vdi --format VDI
The .img is the raw dd dump and the .vdi is the output file.
--format VDIspecifies to output to .vdi format
If you are in a pinch you can always use qemu-kvm binary and manually specify the .img as your disk and i........
1.) Create Image using qemu-img
qemu-img create -f qcow2 skype.img 40G
2.) Start VM using flags
-m = memory in MB
qemu-system-x86_64 -m 4096 -drive file=skype.img -cdrom ~/Downloads/SfB-E-9319.0-enUS.ISO
Enable Bridged Networking........
libguestfs tools howto guide for managing virtual machine images.
libguestfs-tools aka guestfs tools has a lot of tools that make this very easy for you. You can easily mount partitons from an image with some of the commands below.
To mount a partition
#mount the kvmuser102821.img image and the /dev/sda1 partition from it to the local directory "mount"
guestmount -a kvmuser102821.img -m /dev/sda1 mount
qemu-img create -f qcow2 isotest.qcow2 10G
The above creates a "qcow2" format image called "isotest.qcow2" that is 10GB in size.
If you want to preallocate all of the space for increased performance do this:
qemu-img create -f qcow2 isotest.qcow2 -o preallocation=full 10G
It is controlled with the preallocation=full option, of course by default this is set to off........
qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2
Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB
-b the source/base image
-f format is qcow2 and the location of the destination image
What is so special about this? It's even quicker than creating a template with OpenVZ but this is an actual OS.
It saves time a........