11/27/2023 0 Comments Qemu img![]() ![]() Note: qemu 4.x added discard support for virtio-blk too, removing the needing for virtio-scsi for trim to work. This can be checked with du -hs on host side (note: ls -al will not show the real allocated size, just the logical one). If the virtual machine uses virtio-scsi and the libvirt definition include discard='unmap', a simple fstrim on the guest filesystem will release assigned-but-unused free space on the host. In the example we will list information about ubuntu.In addition to the accepted answer (which describe the more common, general method to shrink a qcow2 file), modern versions (ie: RHEL7+) of the libvirt/qemu/qcow2 stack provide the virtio-scsi driver which supports the discard='unmap' option. To get detailed information we will use info command by providing disk image name. As we learned previously the extension is not a sole disk image type shower. Information about a disk file can be needed. $ qemu-img create -f vmdk -o size=20G ubuntu.img Create Vmdk Disk Image Get Information About Disk Image We will also set disk image size 20GB with -o size option. But the extension vmdk do not have an effect on the disk image type. We will set disk file name as ubuntu.vmdk . In this example we will create an vmdk disk image. $ qemu-img create -f qcow2 -o size=10G ubuntu.img Create Qcow Disk Image Create VMDK Disk Image In the example we create a qcow2 formatted disk image named ubuntu.img with the size of 10GB. Now we will set disk size with -o size option. As you remember in the first example we have specified the disk size at the and of the command. We will also provide the disk size as an option. We can create qcow image with the -f option. ![]() Vps is format used by first generation Microsoft Virtualization tool named Virtual PC. It has similar features to the Vmdk and Qcow2 Vpc Vdi is popular format developed Virtual Box. Vmware products like Player, Workstation, ESXi, uses vmdk disk image type. Vmdk is default and popular disk image format developed and user by VMware. It provides support for overlay and sparse images. Disk image format is related with the host system. Disk image format is different than file systems. Disk Image TypesĪs stated before qemu supports different type of disk image formats. Disk image actual size is 0 because there is no data in it but the vm will see disk image as 10G disk and will be able to use up to 10G. The disk image format is raw and size is expressed as byte. $ qemu-img create ubuntu.img 10G Create Disk ImageĪfter disk image create some information is provided. We will provide disk size after disk name which is 10G in gigabyte. In the example the disk image name will be ubuntu.img . We will use create command to create a disk image. Generally all VM’s uses one disk image file to read and write data. Operating system and user level tools are stored in disk image files like physical disks. Virtual Machines or simply VM’s runs operating system and user level tools like normal PC. qemu-img create -f fmt -o options fname size Create Disk Image Syntax of the qemu-img command is like below. ![]() We can get help about the qemu-img command with the -h option. Qemu-img is the tool used to create, manage, convert shrink etc. Disk is one of the most important device in the virtual systems. Qemu is the user space tool used to provide these to the kernel level virtualization tool KVM. ![]() Virtualization creates virtual ram, devices, disks, CPU’s, networks etc. KVM (Kernel Virtualization Module) is an open source, popular and efficient virtualization technology provided by Linux kernel. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |