KVM vs OpenVZ
Understanding the differences between virtualization technologies
On This Page
KVM and OpenVZ represent two different approaches to virtualization, each with distinct advantages and trade-offs.
Overview
KVM (Kernel-based Virtual Machine)
True virtualization where the VPS operates as its own independent server with its own kernel.
- Full kernel control
- Run any OS
- Better isolation
- More stable
OpenVZ
Container-based virtualization that shares the host node's kernel among all containers.
- Lower overhead
- Better CPU performance
- Shared kernel
- Linux only
Detailed Comparison
| Feature | KVM | OpenVZ |
|---|---|---|
| CPU Performance | Good | ✓ Better |
| Network Performance (with virtio) | ✓ Better | Good |
| Disk Performance (with virtio) | ✓ Better | Good |
| Upgrade distro version without reinstall | ✓ Yes | No |
| Can use Windows/BSD | ✓ Yes | No |
| Can change kernel | ✓ Yes | No |
| Can use Docker/containers | ✓ Yes | No |
When to Choose KVM
KVM is the better choice if you need:
- Full Control: Ability to modify kernel parameters and install custom kernels
- Windows or BSD: Want to run non-Linux operating systems
- Docker/Containers: Need to run containerized applications
- Version Upgrades: Want to upgrade OS versions in-place without reinstalling
- TUN/TAP: Need VPN server functionality
- Better Isolation: Require complete separation from other VPS on the host
- Stability: Need the most stable and reliable environment
When to Choose OpenVZ
OpenVZ might be preferable if:
- Cost: Budget is a primary concern (OpenVZ is typically cheaper)
- CPU Performance: Running CPU-intensive workloads on Linux
- Simple Needs: Don't need custom kernels or advanced features
- Linux Only: Only planning to run standard Linux distributions
RamNode Recommendation
We generally recommend KVM for most users due to its flexibility, stability, and broader OS support. The performance difference with modern virtio drivers is minimal, and the added flexibility is worth the slight cost difference.
Important Notes
Not Dedicated Resources
Both KVM and OpenVZ VPS share host CPU and network ports among all VPS on the node. These are not dedicated environments. If you need dedicated resources, consider our VDS (Virtual Dedicated Server) offerings.
Performance Considerations
With modern virtio drivers, KVM performance is excellent for both network and disk I/O. The overhead of full virtualization is minimal on modern hardware.
Migration Between Types
You cannot directly migrate between KVM and OpenVZ. If you want to switch:
- Back up your data
- Order a new VPS of the desired type
- Transfer your data and configurations
- Cancel the old service
Common Use Cases
KVM is Ideal For
- Web hosting with custom configurations
- Development and testing environments
- Running Windows applications
- VPN servers
- Docker/Kubernetes deployments
- Game servers requiring specific kernels
- Mail servers with custom configurations
OpenVZ Works Well For
- Simple web hosting
- Basic application hosting
- Learning Linux
- Budget-conscious projects
- CPU-intensive tasks on Linux
Modern Hosting Trends
The industry has largely moved toward KVM and away from OpenVZ. Most major hosting providers now offer KVM exclusively due to its flexibility and better isolation. RamNode continues to support both for customers who prefer OpenVZ's cost-effectiveness.
If you're unsure which virtualization type is right for your needs, contact our support team. We can help you choose based on your specific requirements and budget.