Servers

Now that we know about the High-level connectivity of Offices, let’s talk about the Individual components and devices that are present in a DC, starting with Servers

So what are Servers, In very basic terms a server is a Computer which is providing any service, notice I am highlighting the Serv part of it, that is the best way to understand, server is something which is serving something to an End consumer, If you are using a Laptop or a desktop at home which serves you in accessing the internet or opening and processing Word or excel files then that laptop or desktop can also be called as a Server as its serving you, now in the IT world this term is mostly used for large computers with High Compute and Memory configuration which does not serve a single user but hundreds of users simultaneously, for e.g. when you are accessing a Netbanking Website from your home or for that matter if you are accessing a plain Google website, that Website is actually hosted on multiple servers in the backend which are processing and serving your requests

To visualize you can start by imagining that the servers are physical boxes just like your desktop but having a different shape and which consists of some high-End CPUs, RAM, Hard disk, Network cards, fiber cards, etc

These Servers are attached / Mounted to the Racks placed in the Datacenter and then the Power, Network and the Storage is connected

The Major players in server manufacturing are:

· Dell

· HP

· IBM

Basically, you would encounter 2 types of server hardware in the datacenter, there are more although:

· Rack Servers

· Blade Servers

Rack servers are 1RU/2RU devices useful for installing standalone Applications mostly but it can be used for other purposes also such as virtualisation or microservices

Blade servers on the other hand are also high-end servers but they are installed in special outer Chassis such that instead of the server getting mounted on to the Rack, the Chassis are mounted on the rack which contains the Blade servers so you can imagine that 14 blade servers can be installed in one Chassis and all the Network or storage connectivity happens via the Chassis connectors

Further the servers can be also used as a Physical Server or a Virtual server, we would learn about the same in the other sections

Physical vs Virtual Servers

Ultimately any Application you use is hosted on a physical server only, because you cannot run any Software without a Hardware, although everything is actually hosted on physical there are 2 typical ways to deploy the Servers and use i.e. Physical and Virtual

Physical

To deploy a server to be used as a physical server you just need to mount the server in the Rack and install an Operating System (OS) such as Windows, Linux, Solaris, etc. "As long as the OS is compatible with the Hardware", once you install the Operating system on the Hardware, then you have an operating system ready to talk to the underlying Hardware and pass on instruction's; Next step is to install your applications on top of the operating system and start using the application, it can be any type of application depending on your requirement such as Web, Application or Database server, don’t worry we would be talking more about the roles of servers in the later sections, so in a nutshell to understand a physical server you need to remember that the OS is directly installed on the Physical hardware and then the application on top of it

Virtual

Using physical servers in the age old days resulted in unoptimized usage of resources such as CPU and RAM, for e.g. an enterprise may buy a high end configuration server for their Business application which may never actually make use of 100 percent resources (CPU / RAM), you find that the resource utilization is not crossing 30 or 40 percent even in Peak times, that means the remaining resources are not getting utilized, to overcome this problem the concept of Virtualization was introduced wherein you can virtualize the server by converting that same physical server into a "Base Host" which can host virtual machines (VMs) on top of it such that the same Business Application can act as a Virtual server and use the 30 percent of resources and the remaining 70 percent can be used by other virtual Machines. So that Deployment goes as follows: Install Physical Server - Install a Hypervisor (Responsible to arrange the sharing of resources to the VMs) - Install VMs on top of Hypervisors - Install Applications on the VMs and use it

In other words, to understand virtualization you should always perceive that when you are connecting to an application which is hosted on a Virtual server then your application VM is not the only VM which is using the base physical server alone; there are other application VMs which would be sharing the underlying physical hardware

There is another method / Technology called as Containerization which is one of the emerging technologies for hosting applications but that’s a Big topic altogether so I won’t be discussing it here but i have a different section where I am discussing the same in detail

Getting back to servers, they can be used as a physical Server or a virtual server