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Virtualization

KVM and Xen, explained honestly

Two real hypervisor options, with the actual tradeoffs laid out instead of marketing language. KVM is our default. Xen is available when you specifically want it.

KVM

Recommended default

Kernel based Virtual Machine. Built directly into the Linux kernel and uses hardware assisted virtualization (Intel VT-x or AMD-V) to run guest operating systems close to native speed.

  • Runs unmodified Linux, Windows, or BSD guests
  • Isolation through Linux cgroups, namespaces, and SELinux
  • Strong live migration and CPU pinning support
  • The hypervisor most modern cloud and VPS platforms run on
  • Generally lower overhead and lower latency for typical workloads

Xen

Available on request

A bare metal, Type 1 microkernel hypervisor. A privileged control domain (Dom0) manages isolated guest domains (DomU), in either paravirtualized or hardware virtualized mode.

  • Supports both PV (paravirtualization) and HVM (hardware assisted) guests
  • Historically valued for its domain isolation security architecture
  • An actively maintained Linux Foundation project, not abandoned
  • Good fit for legacy workloads originally built around Xen
  • A Dom0 compromise has a larger blast radius than a KVM host compromise
 KVMXen
ArchitectureIntegrated into the Linux kernelSeparate bare metal microkernel with Dom0 or DomU split
Guest OS supportUnmodified Linux, Windows, BSDPV needs a modified kernel; HVM runs unmodified guests
PerformanceNear native, low overheadNear native in HVM mode; PV can be lighter for pure Linux
Live migrationMature, widely used in productionSupported, less commonly exercised at scale today
Isolation modelNamespaces and cgroups on a shared kernelSeparate privileged control domain from guest domains
Industry adoptionDominant in modern cloud and VPS infrastructureDeclining broad adoption, still used in specific niches
Best forGeneral purpose workloads, most customersLegacy Xen deployments, specific isolation requirements
Common questions

Choosing between them

Which one should I pick if I am not sure?

KVM. It is our default for a reason: broad OS support, mature live migration, and it is what the overwhelming majority of customers end up running without ever thinking about it again.

Why offer Xen at all if KVM is the default?

Some customers are moving an existing Xen based deployment and do not want to re-architect it, and some specifically want Xen's Dom0 or DomU isolation model. We would rather offer it honestly than pretend it does not exist.

Can I switch hypervisors after I provision?

Changing hypervisors means rebuilding the server, so it is not a live toggle. Open a support ticket and we will walk you through migrating your data to a new instance on the hypervisor you want.

Does the hypervisor choice affect pricing?

Xen carries a small flat surcharge over the equivalent KVM configuration, shown as its own line item in the configurator and at checkout. Nothing is folded into the base price where you cannot see it.

Ready to pick a hypervisor and build?

The configurator shows the KVM and Xen price difference live as you toggle between them.

Open the configurator