Not all VPSs are the same. Two virtual servers advertised at the same price as having ‘4 GB RAM’ can, in practice, perform very differently depending on the technology the provider uses to partition the physical server. KVM VPS is currently the most widespread solution and the one offering the greatest flexibility: even the major cloud service providers rely on it.

In this guide, we explain how virtualisation works, what makes KVM special, how it differs from container-based VPS (OpenVZ, LXC), what ‘guaranteed resources’ mean in practice, who a KVM VPS is suitable for and what it’s used for, and what you should look out for in the first few days.

How does a VPS work?

A software layer called a hypervisor runs on a high-performance physical server, dividing the server’s processors, memory and storage into several isolated virtual machines. Each virtual machine behaves like a standalone computer: it has its own operating system, its own IP address and its own system administrator (you). This is a virtual private server, or VPS for short.

There are two main types of virtualisation, and these determine how much flexibility and what level of predictable performance you get.

What is KVM?

KVM (Kernel-based Virtual Machine) is part of the Linux kernel, which transforms the physical server into a hypervisor. It utilises the hardware virtualisation capabilities of processors (AMD-V, Intel VT-x), which is why virtual machines run at speeds close to that of the physical hardware. It is open-source, evolves alongside the Linux kernel, and even the largest cloud service providers build their services on top of it.

KVM provides full virtualisation: each virtual machine runs its own kernel, with its own virtual hardware. In practice, this means that your KVM VPS behaves just like a dedicated server.

Video: Virtualization Explained (IBM Technology)

KVM or container-based VPS (OpenVZ, LXC)?

With container-based solutions (OpenVZ, LXC), VPSs do not run their own kernel but share the physical server’s kernel; only the file system and processes are isolated. This requires fewer resources, making it cheaper, but it does come with limitations.

Criteria	KVM VPS	Container-based VPS (OpenVZ, LXC)
Kernel	Your own, freely selectable and updatable	Shared with the physical server; cannot be modified
Operating system	Any Linux, BSD or even Windows	Linux that is only compatible with the host’s kernel
Resources	The allocated memory and vCPU are yours	Often overbooked, with ‘burst’ memory
Isolation	With powerful hardware-based virtualisation	Weaker, shared kernel
Docker, VPN, kernel modules	Fully functional	This often involves restrictions or requires special authorisation
Price	A bit more expensive	Cheaper

The difference becomes particularly apparent if you use Docker, WireGuard VPN, custom firewall rules or specialised kernel modules: these work without any issues on KVM, but often do not on container-based VPS. We have written about this topic in more detail.

The benefits of KVM VPS in practice

Guaranteed resources

With KVM, the memory allocated to your VPS is actually yours; other customers cannot take it away, so there is no ‘noisy neighbour’ effect: your server’s performance will not be affected by another customer experiencing peak traffic. This is particularly important for databases, online shops and business applications, where predictable response times are crucial.

Complete freedom

You have root access, run your own kernel, and can install whatever you like: Nginx or Apache, any version of PHP, Node.js, Python, Go, Java, MySQL, MariaDB, PostgreSQL, Redis, Docker and Docker Compose, WireGuard VPN, or your own mail server. You also decide when to update the kernel.

Severe isolation

Virtual machines are physically isolated from one another. A security breach or crash on another VPS will not affect yours, nor will anyone be able to access your files.

Snapshot and restore

With KVM, you can take a snapshot of the entire virtual machine. You can save the current state before a system update or major change, and if something goes wrong, you can revert to it in a matter of minutes. Our knowledge base article covers VPS snapshots.

Hardware matters too

Virtualisation can only deliver as much as the underlying hardware is capable of.

• Processor: the performance per core determines the speed at which individual requests (such as the rendering of a PHP page) are processed, whilst the number of cores determines the number of requests that can be handled in parallel. aWh’s KVM VPSs run on 3.8 GHz AMD Epyc processors.
• Storage: NVMe SSDs connect directly to the PCIe bus and deliver many times the IOPS (input/output operations per second) of SATA SSDs. This makes a noticeable difference for databases and applications that handle large numbers of small files. All aWh KVM VPSs run on NVMe SSDs.
• Network: Bandwidth is crucial when transferring large files and for high-traffic websites. aWh’s KVM VPSs come with a 2 Gbps connection and unlimited traffic.

Who is a KVM VPS suitable for?

• For growing websites and online shops that have outgrown the CPU and memory limits of shared hosting.
• For developers who want their own software environment, a test or staging server, or a CI/CD runner.
• For your own applications: Node.js or Python applications, Docker containers, Nextcloud, n8n, your own VPN.
• For agencies wishing to run multiple clients’ websites on a single server, with their own control panel.
• For game servers and other services that run continuously.

Our separate article provides plenty of examples of what a VPS is good for. If your website fits on a shared hosting plan and you don’t want to run your own server, stick with that: we’ll help you decide by comparing VPS and web hosting.

Do you need system administration skills?

Yes, at least at a basic level. On a KVM VPS, you install and update the operating system yourself, and you configure the firewall, SSH access, the web server and backups. If you don’t have the time or the know-how to do this, you have two options:

• Managed VPS: we take care of server operations (updates, security settings, web server, monitoring).
• Dedicated cPanel: a KVM VPS with a cPanel interface that’s all yours, operated by us; you manage your websites using the familiar cPanel interface.

How much VPS capacity do you need?

A few starting points for Linux servers:

Usage	vCPU	RAM	Storage
A small website, a VPN, a developer machine	1	1–2 GB	10–20 GB
WordPress or a small online shop, Nextcloud for a few users	2	4 GB	40 GB
Larger online shops, multiple websites, Docker containers	4	8 GB	80 GB
High-traffic websites, database servers, multiple services	6–8	12–16 GB	120–160 GB

If you’re also installing a control panel (such as cPanel or Plesk), allow for at least 1–2 GB of memory. aWh’s KVM VPS plans range from 1 vCPU / 1 GB RAM / 10 GB NVMe to 16 vCPU / 32 GB RAM / 320 GB NVMe, from €4.62 (excluding VAT). If you outgrow your current plan, you can upgrade to a larger plan via the client portal; this will increase your processor, memory and storage capacity. The steps for upgrading are described in the article on upgrading VPS resources. We have a separate guide on calculating your VPS resource requirements.

Which operating system should you choose?

AlmaLinux, CloudLinux, Debian, Rocky Linux and Ubuntu can be installed on aWh’s KVM VPS servers, but KVM can run almost any operating system; if you need a system not listed here, please get in touch.

• Ubuntu and Debian: developers’ favourites, with a huge community and plenty of guides.
• AlmaLinux and Rocky Linux: Red Hat Enterprise Linux-compatible, long-term support systems for enterprise software and cPanel.
• CloudLinux: for web hosting services, to isolate users’ resources.

For applications built on Windows Server, a Windows VPS supplied with a licensed copy of Windows Server is the right choice.

Getting started with a new KVM VPS

1. Update the system (apt update && apt upgrade or dnf upgrade).
2. Create your own user account with sudo privileges, and avoid working as root.
3. Set up SSH key-based access and disable password and root access. The steps are described in the article on connecting to your VPS via SSH.
4. Enable the firewall and only allow the necessary ports (SSH, HTTP, HTTPS). This article on configuring the VPS firewall will help you with this.
5. Enable automatic security updates.
6. Install the necessary software or a control panel.
7. Set up your own backup alongside the provider’s daily backup, and take a snapshot of the current operational state.

You can read about server-side security settings in detail in our VPS security guide.

aWh’s KVM VPS services at a glance

• 3.8 GHz AMD Epyc processor, NVMe SSD storage
• 2 Gbps connection, unlimited traffic, IPv4 and IPv6 addresses
• Daily backups and snapshots
• DDoS protection, 99.9% uptime
• Docker and LXC support, root access
• European Union data centre
• Support, 14-day money-back guarantee

Check out the KVM VPS plans

Frequently Asked Questions

What is the difference between KVM and OpenVZ?

KVM provides full virtualisation with its own kernel and guaranteed resources, whilst OpenVZ is container-based; VPSs share the physical server’s kernel. Any operating system and software can be run on KVM, whilst on OpenVZ only Linux distributions compatible with the host kernel can be used, and certain software (Docker, VPN, kernel modules) operates with limitations.

Can I run Windows on a KVM VPS?

KVM is technically capable of this, but a licence is required for Windows Server. At aWh, Windows VPS, which comes with a licensed copy of Windows Server, is the solution for this.

Do you need system administration skills for a KVM VPS?

Yes, at a basic level: you’ll need to configure the system, the firewall, the updates and the applications yourself. If you’re not up for that, opt for a managed VPS or a dedicated cPanel.

What is the difference between a KVM VPS and a dedicated server?

A KVM VPS is a partitioned section of a physical server with guaranteed resources, whilst a dedicated server is an entire physical machine. A VPS is cheaper, can be scaled up more quickly and you don’t have to worry about hardware faults; you need a dedicated server if you require more resources than even the largest VPS can provide.

Is a KVM VPS more secure than shared hosting?

The isolation is stronger, but you are responsible for the security of the server. An up-to-date, well-configured KVM VPS is very secure; a neglected one, however, is more vulnerable than shared hosting operated by a provider.

Which control panel can I use?

Any of these that run on your chosen operating system: cPanel (with a licence, on AlmaLinux or CloudLinux), Plesk, DirectAdmin or free alternatives such as HestiaCP. An article comparing control panels for VPS will help you make your choice.

Is there an automatic backup?

Yes, daily backups are taken of every aWh KVM VPS, and you can also create a snapshot at any time. It’s worth keeping your own backup of important data, separate from the server.

How do I migrate my website to a KVM VPS?

Install the necessary software (web server, PHP, database) or a control panel, copy over the files and the database, test the site, then point the domain to the new IP address. If you get stuck, do get in touch.

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