KVM (Kernel-based Virtual Machine) is hardware virtualization technology built into the Linux kernel. KVM turns your VPS into a virtually full-fledged dedicated server with complete system control.
Why KVM is the Best Choice for VPS
Complete Isolation. Your VPS operates as a separate physical server. Neighboring VPS cannot affect your performance.
Guaranteed Resources. CPU, RAM, disk specified in the plan—that's exactly what you get. No "sharing" with neighbors.
Full Root Access. You control everything: from Linux kernel to network settings. You can install any OS, modify kernel, configure system-level firewall.
Own Kernel. Unlike container virtualization (OpenVZ, LXC), you manage your own operating system kernel.
KVM vs Other Virtualization Types
KVM vs OpenVZ
OpenVZ (container virtualization):
- ❌ Shared kernel for all containers
- ❌ Cannot modify kernel parameters
- ❌ Software installation limitations
- ❌ Neighbors can affect performance
- ✅ Cheaper and more lightweight
KVM (hardware virtualization):
- ✅ Isolated kernel
- ✅ Full system control
- ✅ Install any software
- ✅ Stable performance
- ✅ Can install Windows
Conclusion: OpenVZ is suitable only for basic tasks. For serious projects—only KVM.
KVM vs Hyper-V
Hyper-V (Microsoft):
- Proprietary technology
- Optimized for Windows
- Limited Linux support
KVM:
- Open source
- Native for Linux
- Excellent performance
- Wide distribution support
KVM vs VMware
VMware ESXi:
- Paid license (expensive)
- Closed source
- Used in enterprise
KVM:
- Free open source
- Built into Linux kernel
- Same performance
- Ideal for hosting providers
What KVM Gives You as a User
1. Install Any Operating System
You can install:
- Any Linux distribution (Ubuntu, Debian, CentOS, Arch, Gentoo, Fedora)
- Windows Server (2012, 2016, 2019, 2022)
- FreeBSD, OpenBSD
- Specialized OS (pfSense, VyOS)
On OpenVZ, you're limited to what the provider preinstalled.
2. Modify Kernel Parameters
You can configure:
- Network stack (for high loads)
- File system
- Kernel modules
- Security parameters
Example: Kernel tuning for 100,000 simultaneous connections on web server.
3. Work with Low-Level Technologies
What you can do:
- Docker containers
- Kubernetes clusters
- Nested virtualization (virtualization within virtualization)
- Any type of VPN servers
- Custom firewalls and routing
Example: Running Kubernetes for microservices orchestration.
4. Snapshots and Backups
KVM allows full system snapshots:
- Save entire server state in seconds
- Rollback to previous state
- Server cloning
Example: Before update—snapshot, update, if something breaks—rollback in a minute.
Tasks Where KVM is Critical
- Custom configurations — need kernel tuning or special modules
- Docker/Kubernetes — container virtualization requires KVM
- VPN servers — OpenVPN, WireGuard need full network access
- Windows Server — only KVM supports Windows
- High loads — guaranteed resources without neighbor interference
- Development — testing on different OS and configurations
KVM Performance
Near-native performance — KVM runs almost as fast as a physical server. Performance loss: 2-5%.
Tests show:
- CPU: 98% of physical server
- RAM: 99% of physical
- Disk I/O: 95-98% (on NVMe)
- Network: 99%
For comparison, OpenVZ gives 70-85% performance under high loads.
Real-World Example
E-commerce store on 1C-Bitrix:
On OpenVZ:
- With 100 concurrent visitors: lags
- Catalog import from 1C: freezes
- Search indexing: CPU 100%, other processes halt
- Backup: affects site operation
On KVM:
- 500 concurrent visitors: stable operation
- Catalog import: runs in background, site works
- Indexing: doesn't affect users
- Backup: invisible to visitors
When You Can Skip KVM
If you have:
- Simple static HTML site
- Basic WordPress without load
- Minimal performance requirements
- No need for customization
But even for such tasks, KVM is better—you're protected from neighbor problems.
Technical Details
QEMU + KVM: KVM uses QEMU for device emulation, but virtualization itself goes through processor (Intel VT-x, AMD-V).
Paravirtualization: KVM supports VirtIO drivers to accelerate disk and network operations.
Memory ballooning: Dynamic memory management for resource optimization.
CPU pinning: Binding virtual cores to physical ones for maximum performance.
KVM Myths
"KVM is slower than physical server" Performance loss is 2-5%. For most tasks, the difference is imperceptible.
"KVM is harder to manage" Management is the same as on a regular Linux server. No special knowledge required.
"You can't run Windows on KVM" You can! KVM excellently supports Windows Server of all versions.
Need Dedicated Server Power at VPS Price?
All our VPS run on KVM only. Complete isolation, guaranteed resources, root access.
FAQ
Can I modify Linux kernel on KVM VPS?
Yes, you have full kernel access. You can install any kernel version, compile custom kernel, modify parameters.
Do neighbors affect my VPS?
No. KVM ensures strict resource isolation. Even if a neighbor maxes out their CPU—your VPS won't suffer.
Can I run Docker on KVM?
Yes, Docker works excellently on KVM. Moreover, Docker requires full virtualization and won't work on OpenVZ.
Is KVM suitable for Windows Server?
Yes, KVM is one of the best platforms for Windows Server. Full support for all Windows features.