qemu-img KVM create disk image howto

 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 (so not using -o preallocation really silently results in -o preallocation=off).

If you want to resize an image check ths out.

How to create from a template/backing image?

qemu-img create -f qcow2 newimagefile.qcow2 -o backing_file=yourfile.qcow2 10G

newimagefile.qcow2 is the new image you are created

yourfile.qcow2 is the base/template image that it is based off (eg. maybe you installed Windows or Linux to yourfile.qcow2 and you want to start from that point so the combined image will be the difference of the original "backing file" vs the changes you make which are reflected in newimagefile.qcow2 (so don't move or delete the original backing file yourfile.qcow2 or you will lose your data).


Tags:

qemu, img, kvm, disk, howto, qcow, isotest, creates, quot, format, gb,

Latest Articles

  • Linux Ubuntu Cannot Print Large Images
  • Cannot Print PDF Solution and Howto Resize
  • Linux Console Login Screen TTY Change Message
  • Apache Cannot Start Listening Already on 0.0.0.0
  • MySQL Bash Query to pipe input directly without using heredoc trick
  • CentOS 6 and 7 / RHEL Persistent DHCP Solution
  • Debian Ubuntu Mint rc-local service startup error solution rc-local.service: Failed at step EXEC spawning /etc/rc.local: Exec format error
  • MySQL Cheatsheet Guide and Tutorial
  • bash script kill whois or other command that is running for too long
  • Linux tftp listens on all interfaces and IPs by DEFAULT Security Risk Hole Solution
  • python import docx error
  • Cisco Unified Communications Manager Express Cheatsheet CUCME CME
  • Linux Ubuntu Debian Missing privilege separation directory: /var/run/sshd
  • bash how to count the number of columns or words in a line
  • bash if statement how to test program output without assigning to variable
  • RTNETLINK answers: Network is unreachable
  • Centos 7 how to save iptables rules like Centos 6
  • nfs tuning maximum amount of connections
  • qemu-kvm error "Could not initialize SDL(No available video device) - exiting"
  • Centos 7 tftpd will not work with selinux enabled