KVM, Xen and OpenVZ describe virtualization technologies, not comparable hosting plans by themselves. First determine whether the offered instance is a virtual machine or an operating-system container, then check kernel control, guest support, resource policy and recovery access. The technology name alone cannot rank performance, privacy or reliability.
KVM: virtual machines with guest kernels
KVM's project overview describes full virtualization integrated with Linux and commonly used with QEMU. A guest runs its own operating system against virtualized devices. Actual support for an OS, custom ISO, kernel or passthrough device depends on the provider's platform and plan.
Guest control is not equivalent to ownership of a dedicated physical CPU or storage device. Ask about scheduling, storage limits, supported drivers and available recovery tools.
Xen: identify the actual guest mode
The Xen Project handbook distinguishes PV, HVM and hybrid approaches such as PVH. These modes have different guest and hardware requirements. Do not assume every Xen offer uses the same mode or that age establishes greater stability than another hypervisor.
Request the supported guest images, kernel expectations and console or rescue method. Guest drivers must match the actual platform; KVM's virtio terminology should not be used as a generic name for Xen drivers.
OpenVZ: containers are not the whole product label
Traditional OpenVZ containers share the host kernel while separating application environments. That limits independent kernel changes, but it does not mean there is no isolation. The OpenVZ user's guide also documents KVM-based virtual machines in the broader platform. Ask which instance type and release a provider actually offers.
For a container, verify required kernel facilities, permitted capabilities and application compatibility. For a VM, verify the corresponding guest and hardware-virtualization requirements.
Use a compatibility checklist
- Does the application need a particular guest OS, kernel module or nested virtualization?
- Are CPU, memory, storage throughput and network limits documented?
- Can you access a console, reinstall, restore and export data?
- Who patches the host layer and who patches the guest or container environment?
- Does a representative workload meet your own latency, throughput and recovery criteria?
Compare like-for-like workloads and plan limits instead of repeating an unsourced universal speed ranking. For the basic service model, read the VPS explanation only if it matches your question; consult current VPS specifications for WebCare360's actual offer. WebCare360 is the provider publishing this comparison.
