When we talk about VMWARE ESX servers and the virtual environment (virtualization), we actually need to start from understanding what are the virtual machines all about. A virtual machine or virtual computer means that it is a computer & operating system as we know it, only it is based on software (not hardware). Which means all of its characteristics are based on software definition hosted on a physical machine.

To simplify this explanation without going too deep into the technical measures, it is a definition of what a computer needs to be (emulating its exact environment) only those definitions are based on a program that is a configuration of that environment in order to emulate a real computer, but there are no physical parts, they are sort of a logical part.

The resources which are configured for the creation of that virtual machine are being taken from a physical machine, which allocates those resources from the physical machine to the virtual computer. Now since we are allocating part of the real physical sources, we can use the remaining resources to create another instance (another virtual computer), which can use other free resources. So, if we have many resources on a physical computer, like for example a physical 4GB RAM, which we then allocate 1GB of RAM for each virtual machine, we actually get 4 different virtual computers with 1GB RAM, that can be installed with different operating systems, like Linux, different versions of Windows operating systems, either desktop or servers.

Now if you understand that concept, you now realize that you can test any type of computer or operating system, by raising it virtually, test it, and delete it, without destroying or re-installing your own computer. You just host those virtual machines on the same computer you are working on. Many use those types of ESX servers, to create different types of computer machines to enable the testing environment, without purchasing another hardware. For the same price of having a strong server computer, you can get many different servers or desktop, hosted on the same machine, which only shares it’s resources with those virtual servers and saves the cost of purchasing a separate computer for each computer we need to use.

What is an ESX Virtual Server? Well, it is the environment that enables us to place upon it and manage many different virtual machines (desktop, server computers, with different types of operating systems). ESX Server is one of the most used virtual servers, even though the Microsoft Hyper-V virtual server is starting grasp hold in this market, ESX servers are still the most used ones.

The options you can use are:

1. You can dedicate a strong physical server, and install the ESX server operating system on it, which comes as a full environment, which you manage using an external management client (which you can install on your desktop computer) and only certain definitions can be defined using the ESX server management console.
2. You can decide you want to use the ESX Desktop server version, which enables you to host virtual machines, on your desktop computer (no server hardware is required). Now since it is not a server, the number of virtual computers you can operate online at the same time will rely on the number of resources your desktop computer has. You can create many virtual machines if you have the hard-disk capacity for it, but you will be able to get only one of them online, in case you do not have enough memory, for example.

Advantages of Virtual machines on ESX Servers:

1. You can host many different types of computers on one computer (Cost-effective, as you don’t have to spend more money on another hardware computer)
2. You can backup a whole computer (a whole virtual instance) and recover it completely very quickly. (This is a better, quicker solution for backing your whole hardware computer’s operating system, and recover from it, like when you use Norton Ghost).
3. Installation of new servers (virtual servers) is much faster than installing them on a regular physical computer.4.

Disadvantages of Virtual machines on ESX Servers:

1. You need a stronger computer/server to use the ESX server on, in order to utilize many hosted virtual computers at once.
2. If an ESX server crashes, and you have multiple virtual computers/server running on it, they will all go down at once.

Downloading ESX server and start working:

• Follow the instructions on this link – Download ESX Server 3.5
• Installing ESX server – step by step.
• Virtualization Simplified – Guide to Server Virtualization
• Virtual Machine backup guide
• How to install VMware ESX 3.5 inside VMware Workstation 6.5 – Video lesson
• Live IT. Love IT. VMware IT – Comic Video presentation of VMWARE 🙂

Summarizing: There are many benefits to using virtual servers, to be able to have the flexibility and ease of installing new servers, and raising a server environment quickly and more securely. But do not forget that it is risky to place all of your eggs in one basket, so for really important servers that server your network you might want to create a more solid infrastructure is at least a contingency solution in case of a disaster.

What is the virtual machine/virtual server, and why has this issue became such a needed and common solution for organizations?

The virtual machine provides a tool that can run different applications, operating systems on the same machine as if it was a physical computer. The idea is that you can install either a full VMware server (virtual server), that is designated to run different operating systems simultaneously. This means you can install several servers on one hardware machine, and they all will work fine as if they were all different physical servers.

This shows that on one hardware physical computer, we can run different servers and services, and save the cost of buying other hardware machines. This solution enables many different advantages which are not just cost-effective but more flexible and for different purposes that benefit organizations.

Virtual services for QA purposes: Usually QA (Quality assurance) department, needs to simulate a certain environment to enable the testing as close to the real environment where the application/device will be running. When you know a client has a specific network environment, or a specific server that he needs our application to run upon, we will need to do testing of our development on that environment.

The simplicity of it all is that without buying a specific hardware, installing the environment of the client on that hardware and then do out testing. We can just install the environment on a virtual server, do our testing, play around with it (since it is a server (we installed) for the testing purposes and it is not a real server that serves others) and when we are done, we can shutdown this environment we built, and clear the space for our next QA project.

Virtual servers for support: When we need to give a client support, and we stumble upon a situation where we can’t reach a solution since the client is using an environment that we do not have on our system and we want to simulate exactly the environment the client has, so we could see the same problems he encounters. We can build such an environment easy, simply by creating the virtual system the client uses, install all of the applications he is using, and then our system, to test and see what he stumble upon, and find a solution locally on our system.

Again when we are done, we can just remove that server, and clear space for a new server to be installed. This is the flexibility the virtual environment enables us to use.

Virtual servers for multiple organization services: The virtual server can run multiple servers at the same time on the same machine. There are servers organization uses, that do not need many resources to run, like a monitoring server, or a DNS server, or a DHCP server, etc…

Those servers, without the virtual environment, will have to be installed separately on different hardware machine, so for each of the server I mentioned Monitoring server, DNS and DHCP servers, we will be keeping 3 different hardware computers, and on each one, we will install a different server.

You can understand that we are keeping 3 hardware servers, for applications that probably will not even use all of the hardware PC/Server resources it will be installed on, and we will be wasting valuable resources, and of course, it occupies more space on our server room (3 servers take more space than one).

Virtual servers enable us to reduce cost, be more efficient, configure the exact resources and image requires for proper function and be more efficient by maximizing the use of one hardware server, with multiple solutions on one machine.

Virtual server as a reliable backup system: When we install instances/images (each instance represents a different server on a virtual machine), we can define a schedule that will save the instance snapshot or a full exported file of the whole instance.

This enables to restore into a previous snapshot, in case we caused damage to the server, or restore the image fully, in case it is malfunctioning and we can’t use it anymore, so we restore from the last exported image (which is a stored file of the whole operating system with everything on it), a process that can take around 30 minutes maybe less, depends on the size of the server and how much was installed. This saves the whole re-installation process from scratch, and re-deploy of all the necessary applications, and their configuration to make them run, as the original server

did.

Anyone who uses NORTON GHOST to keep a whole computer image backup knows how simple it makes the restore operating and of course saves time and the headache of needing to re-install re-configure everything from scratch.

These are the most important benefits of using a virtual server, and I would have to say that you will need at least one virtual server on an organization just to enable a flexible environment for IT to use, in case a quick server needs to be deployed for a very urgent project.

• Microsoft Virtual Server
• Windows 7 – Virtual PC
• VMware server