QCOW2
QCOW2 Disk Image
QCOW2 (QEMU Copy On Write v2) is a disk image file format for hypervisors that supports dynamic allocation, compression, and snapshots.
What is QCOW2 Disk Image?
Developed by the QEMU project, QCOW2 is widely used in virtualization environments with KVM and QEMU. The format uses a copy-on-write mechanism, meaning the disk image only grows as data is written to it, saving physical storage space. It also supports advanced features like multiple snapshot levels, AES encryption, and internal image compression, making it a flexible choice for testing, development, and production virtual machines.
Advantages
- Dynamic disk allocation saves physical storage space
- Supports internal and external snapshots
- Built-in AES encryption for data security
- Optional internal zlib compression
- Easily convertible to formats like VMDK and VHD using ConvertX
Limitations
- Slower performance compared to raw disk images due to overhead
- Metadata fragmentation can degrade performance over time
- Recovery can be complex if the image metadata is corrupted
How to open QCOW2 Disk Image files
QEMU
KVM
Virt-Manager
Proxmox VE
GNOME Boxes
Common use cases
- Running virtual machines in KVM/QEMU hypervisors
- Creating disposable virtual machine snapshots for testing
- Deploying thin-provisioned virtual appliances
- Migrating virtual disks between different hypervisor formats
Explore other formats
Frequently asked questions
QCOW2 stands for QEMU Copy On Write version 2. It is a disk image format designed for virtual machines.
Yes, you can easily convert QCOW2 to VMDK and other virtual disk formats using ConvertX tools.
QCOW2 uses thin provisioning and dynamic allocation, meaning the file only consumes space for the data actually written to the virtual drive.