What’s a Server?

Sometimes there's terms that we come by that we just throw around and we think we know what the definition is, and I feel like server is one of those. If we were to actually sit down and think, what is the definition of a server, then we would actually scratch our head and say, well, really, what is the definition of a server? So let's define what a server is.

Three components

The term server, I feel like, really represents three different components, one of which is the most important.

Let's say right here we have a client that's using an app. Maybe that app is Chrome and they're browsing the web, and they're making it to our server, which is providing some sort of service. Maybe we have Apache running on here that's delivering our web services, so we want to deliver those web services to this client right here. So Apache is one component: we have the program, or the software, component of this.

The next aspect of this is the operating system. There are specific server operating systems; Windows Server is an example of this, and Debian is used a lot as a server. So there are specific OSes that are specifically designed as servers.

Then we also have the hardware. I can go out to a site like Dell and purchase a server, and it's a piece of hardware and it can show up on my doorstep.

So what exactly is a server? I mean, here we have the software, we have the OS, we have the hardware. What's really needed? Well, I can install Apache on just my home laptop, and I can have the laptop and turn it into a server. So when we talk about servers, I really think like this is the true aspect of what a server is: it's delivering services to our end clients. However, we do have certain operating systems that are really designed more to help deliver these services, so there are specific OSes that also kind of align to this definition as well. And then we have the hardware aspect that also aligns to this.

From physical hardware up to the service

I wanted to give you a glimpse into what a server might look like. For the physical server, we might actually go to Dell and purchase a physical server, and then it would show up and then we would need to install an operating system on it.

What I've done is I've taken my Dell server and installed ESXi on this. ESXi is a hypervisor, so a hypervisor allows me to turn up many virtual machines. So I could then run a version of Ubuntu on here, and Debian, and also Windows Server, and I could host out multiple servers from here. And then on top of that, then I would install Apache, and that would actually deliver the service.

So I just wanted you to see that there's this physical layer, then there's this operating system that needs to happen on top of that, and then there's the actual service itself, like Apache, that we're going to be running. But all of those would really be considered a server.

Inside a physical server

Here's an example of a physical server. What we can see here, first of all, is that it's just designed to mount on a rack. Now, not all physical servers are designed to mount on a rack, but this one is in particular, and that's pretty standard.

Now I can also open this up, and what I see on here is there's a lot of components within here that you wouldn't typically see on a regular machine. You could use this as just a regular desktop machine, although it's geared more towards servers.

So what makes it more of a server and geared towards offering services? We see two central processing units on here. It's capable of adding a ton of RAM onto here; I think it's over a terabyte of RAM that can be added to this. We see redundancy here with fans, that's a fan right there, so we've got lots of fans. We see hard drive redundancy over here. So there's just a lot that's built into here that's designed for serving out content, that you wouldn't see on a regular desktop.