First of all, technically
VDS adopts full virtualization technology to provide a completely independent virtual server environment, which is equivalent to a real physical machine. Various types of operating systems can run simultaneously on VDS. Typical technical platforms are VMware, Hyper-V and so on.
VPS is mainly a virtualization technology based on software layer, that is, operating system-level virtualization. It may not use the virtual hardware environment, but it needs to make some necessary modifications to the guest operating system. Typical technical platforms are Virtozzo and OpenVZ.
In addition, it is worth mentioning that in practice, everyone is used to classifying Xen as VPS, but the quasi-virtualization technology it uses is more similar to VDS in characteristics, so it is also ambiguous.
Second, resources.
Once resources such as CPU, memory and bandwidth are allocated by VDS, they will always be used only by themselves. Before running, hardware resources will be allocated in advance, and the resources that can be allocated must not exceed the maximum resources that can be allocated by the physical machine, that is, if the physical machine has 2G memory, it can never allocate 4G. Swapped the memory.
The occupation of CPU, memory and bandwidth by VPS is shared, and each VPS will affect each other. Its resource allocation is unrestricted. For example, if the physical machine is 2G memory, you can virtually allocate 4G, but it doesn't make much sense. There is no swap memory.
Therefore, VDS is obviously a more stable and reliable choice in resource allocation. VDS is rare among virtual service providers, while VPS is the most popular and cheapest.
Third, in terms of quantity.
In terms of the number of virtual machines, VDS is more suitable for applications that require high stability and reliability, so usually only about 3-4 VDS will run on a physical machine. However, VPS is obviously more efficient than full virtualization because of its low overhead, so VPS running on a physical machine can usually run 20-40 VPS. Theoretically, V can virtualize hundreds of independent operating systems on a server, but the result is predictable and meaningless.
Fourth, in terms of security.
VDS is completely independent of hardware resources and systems, so when it is attacked, it usually does not affect other VDS on the same server. But VPS always share resources on the same server, so when one VPS is attacked, it will directly affect the operation of all other VPS. In addition, because VPS does not exchange memory, once the used memory exceeds the allocated memory, it will directly lead to the collapse of VPS; Because VDS has swap memory, it will not crash immediately if it exceeds the standard seriously, but the system response will be slow. Generally speaking, they all enhance the capability, safety and reliability of physical machines.
Fifth, the cost.
From all aspects, VPS is lower in cost than VDS.