Virtual Private Servers - the Basics

A virtual private server can be described as the next step after shared web hosting on the way to your own dedicated server. Virtualisation plays a significant role in web-hosting, as server hardware is becoming more efficient and affordable in terms of memory and CPU performance. As a website owner, virtual private servers offer you the benefits a dedicated server offers but at only a fraction of the price.

What are the main benchmarks of the virtual private server?

- physical memory;- disk space;- CPU allocation;- bandwidth;- operating system

Physical memory

Physical memory (RAM) determines the number of applications you can run on your VPS at the same time, and how many users can access these applications simultaneously. here we go again This is usually translated into "how many users can I allow on my site without the site slowing down?". Naturally the more memory you have is available, the better. However, the majority of virtual private servers plans offer memory between 512MB and 4096MB. Anything below this limit will make it difficult to perform anything other than running a proxy server or a domain nameserver. Anything above that, and you're advised to consider moving to a dedicated server, not only because 4GB of memory is likely to be quite expensive when allocated to VPS servers, but also because a dedicated server still provides more performance than VPS with the same specifications. Additionally, in the event that your VPS already has 4GB of memory, the scales could begin to tip in favour of dedicated servers.

Disk space

The majority of VPS deals provide between 5 and 40GB of disk space. If you do not intend to host a large number of large files (such as high resolution images or media files) the space allocated is likely to be adequate. Be aware that larger amounts of space will eventually become more expensive with a VPS plan than with a dedicated server, just like with memory.

Allocation of CPU

Another important aspect is the way in which CPU time is allocated to your VPS. There are a myriad of models however all have one thing in common: make sure you inquire about the exact CPU that is being used by your VPS node. It's a big difference if your node is running an E3-1230 processor or an old P4! Below is a quick summary of the most common CPU allocation plans:

1. A guaranteed cores plan offers you complete control over the specific number of cores that are available on the host's CPU. While this option gives you the most in terms of CPU performance compared to other allocations, it is also the most expensive one because a significant portion of a CPU's processing time is reserved for you alone regardless of whether you really need it or not. 2. The allocation of MHz/GHz ensures you an amount of continuous CPU performance, based on the CPU's clock speed. 3. The number of cores or fair share: this method gives you a certain number of cores that are part of the physical CPU of your VPS node. If your VPS plan states "2 cores fair share" it means that you'll be able to use 2 cores of the physical CPU to run your VPS and you can use these two in such as to not cause an issue for other clients on the same node also making use of these two cores. The provider will define "fair share" differently, so make sure to check the fine print. 4. vCPU: this allocation is a mix of (2.) and (3.) - it might feature allocations such as "4 cores at 800MHz", etc. Keep in mind to inquire as to which CPU is used in your VPS node.

Bandwidth

VPS servers have lower bandwidth and traffic than dedicated servers. They are typically connected to a 100mbit/s connection (sometimes shared) Some providers offering gbit/s on default or through an upgrade. Although it is tempting to purchase the most bandwidth you can get, this is likely only a sales tactic. To avoid unnecessary costs, make sure you know the amount of traffic your company will be using.

Operating system

The majority of VPS will be running any of the popular flavors of Linux like CentOS, Debian, Ubuntu, Fedora, etc. There is no restriction to only using Linux, however. Most providers will offer Windows based virtual private servers, too. However, they will usually come with additional licence cost.

Summary

A VPS has the benefit of being small. You can do nearly everything you can do with a dedicated machine, but you still get a much lower price than purchasing a whole server. The disadvantages of virtual private servers lie in their contention ratio and scalability.

You will encounter increasing competition for resources between guest systems. Scalability is another issue , as you cannot scale up an VPS without stopping. The current hardware of everyday's high-performance Intel or AMD architecture cannot be scaled infinitely and a website that requires resources that were normally accessible via dedicated servers a few years ago might even benefit from the extra performance (albeit at a higher cost) from an individual machine that has the same specs as memory, CPU and disk space.