How many types of server can you name in a minute? This is my list: cloud servers, dedicated servers, bare metal servers, bare metal cloud servers, virtual servers, virtual private servers, hybrid servers, infrastructure-as-a-service, metal-as—a-service. It’s a bewildering list for anyone who isn’t a server hosting insider, and I’m sure I’ve missed a few. Each captures something important about the product on offer, but in reality most are variations on a simpler distinction, that of dedicated servers and virtualized servers.
The Difference Between Dedicated & Virtual Servers
Dedicated servers are physical machines. You can pick up a dedicated server. If you dropped it on your foot, it would hurt. Virtualized servers are not physical machines; they are a software construct. Virtual servers run on dedicated servers, the resources of which are divided between several virtual servers.
You can think of virtualization in layers. The RAM, processor, hard drive, and other components of the dedicated server are the bottom layer. The dedicated server runs an operating system. On that operating system runs a hypervisor. The hypervisor in turn runs and manages a number of virtual servers, which communicate with the dedicated server’s operating system, and hence the underlying hardware, via the hypervisor.
To sum it up, the layers of a virtual server roughly look like:
Hardware > Operating System > Hypervisor > Virtual Servers
Benefits of Virtual Servers vs. Dedicated Servers
Virtualizing servers has many advantages vs dedicated servers, both for the hosting provider and the client.
Virtualization allows a server hosting provider to divide an expensive dedicated server between several clients, reducing the cost for each. Creating a new virtual server is as simple as running some software, so they’re ready more quickly than a dedicated server, which has to be physically connected and configured.
Some types of virtual server can be created and destroyed by the client in seconds. They only pay for the server for as long as it exists and consumes resources. Virtual servers like this are usually called cloud servers. Virtual servers made available on longer, frequently monthly or yearly, contracts are typically called virtual private servers, although some vendors confusingly refer to them as cloud servers too.
Virtual servers are typically more flexible, scalable, and agile over short periods of time.
Benefits of Dedicated Servers over Virtual Servers
All that said, there are some situations in which a dedicated server is preferable.
The major benefit of dedicated servers, which are also called bare metal servers, is power and performance. Dedicated servers are the most powerful server hosting option available. Virtualization can, in limited cases, cause resource contention issues that impact performance. Dedicated servers don’t suffer from this particular problem. If performance is the most important factor, then a dedicated server is the right choice. Dedicated servers are also excellent for predictable workloads, or workloads that don’t change quickly enough to require the by-the-minute scalability of cloud servers.
Dedicated servers are single-tenant environments: only one client has access to the hardware. Virtual servers are multi-tenant environments: a client has sole access to the virtual server environment, but they share the hardware with two or more clients. Although the security implications of a multi-tenant hosting environment are minimal, some server users prefer the privacy of a single-tenant environment.
Both dedicated servers and virtual servers have a role to play, and hopefully this article has helped you understand the key differences between them.