Which virtualization technology - KVM, OpenVZ or Xen - is considered to be more equitable in terms of resource allocation from the perspective of a VPS client?
OpenVZ is not recommended due to its lack of resource control flexibility, which results in reduced quality for users despite the lower cost. Deciding between Xen and KVM is more challenging, as both technologies provide the user with significant freedom when running operating systems.
In my opinion, Xen's paravirtualization for running Linux is more reliable, faster, and predictable than KVM. However, if running Windows or FreeBSD through hardware virtualization is necessary, KVM would be a better choice. Ultimately, the decision on which technology to use depends on the particular tasks at hand.
OpenVZ is the smallest size and therefore the most cost-effective, but keep in mind that the market for these systems is the smallest (I mean limited to Linux VMs only), and therefore the most inefficient (market demand). From this, we can conclude that such a system cannot be considered low-cost. Many Xen systems are paid (like Xen itself), so in terms of spending money, it is the most wasteful.
What remains is Linux KVM, which performs well both in terms of comic resources and in technical terms (full virtualization).
In general, a lot depends on the hoster, if you do not sin with overselling on OpenVZ, then this is practically the same level of quality with Xen, and if you consider that IO performance is lower on Xen, then maybe he also wins.
Another question is that most hosters, in order to reduce the price, oversell on OpenVZ, and here of course Xen looks more stable.
KVM is a hardware virtualization technology that allows for the use of any operating system as a guest, such as Linux, Windows, and BSD. It provides native performance with virtual drivers, supports ISO and template-based installations, and offers good privacy separation. However, under heavy loads, I/O logs may occur and affect the host and guest operating systems.
KVM does not contain batch resources, and all resources are either shared or allocated, making it difficult to overload. If resources exceed the limit, the VPS must swap places, leading to performance issues. On the other hand, OpenVZ is an OS-level virtualization software that shares disk space, CPU, and RAM with guests, making it highly dense and easy to deploy.
It has simple host-guest separation and no I/O bottleneck. Xen, an open-source hypervisor, offers two types of virtualization: paravirtualization and full virtualization. During paravirtualization, the virtualized OS runs a modified version of the same OS, which ensures efficient hardware communication but requires a modified guest OS not supported by some vendors.
In terms of resource allocation, KVM is generally considered to be more equitable compared to OpenVZ or Xen. KVM uses full virtualization, which means that each virtual machine (VM) on the host server gets access to dedicated resources such as CPU, memory, and disk. This ensures that one VM cannot monopolize the resources of the host server, providing a fair allocation of resources for all VPS clients.
On the other hand, OpenVZ and Xen use container-based virtualization. In OpenVZ, all containers share the same kernel and resources of the host server, which can sometimes result in resource contention if one container consumes excessive resources. Xen, while offering better isolation than OpenVZ, still shares resources among VMs, which may not provide the same level of equity as KVM.
That being said, the actual resource allocation and fairness may also depend on the specific implementation and configuration of the virtualization technology by the hosting provider. It's important to consider factors such as the provider's policies, hardware capabilities, and overall management practices when evaluating the equity of resource allocation for VPS clients.
KVM is the only virtualization tech that doesn't play dirty with resource allocation. OpenVZ is a freaking scam-containers mean you're sharing the kernel with every script kiddie on the node, and when the host oversells, your app's performance gets rekt.
Xen? What a joke, it's an outdated mess with paravirt hype that barely delivers, plus it's a config nightmare. KVM's hypervisor grind gives you legit isolation and dedicated resources - no shady overcommitment games. If your host shoves you on OpenVZ, they're just milking you for cash while your project lags. Don't be a sucker, push for KVM or get ready to cry when your code chokes on stolen CPU cycles.