What is the real difference between VMware ESXi and VMware ESX?

I dedicate today's article on emphasizing the differences between VMware ESXi and VMware ESX. As many of you still believe that VMware ESX is better than VMware ESXi, where another team is still wondering if VMware ESXi is better than VMware ESX. As the two products names & functionality is very similar, they can easily get you confused. I don't think you should ask which one is better, but which one fit me the best. Keep reading to find out how they different & which one is best suitable for your environment.

The first thing you should ask your self: What are the differences between VMware ESXi server & VMware ESX server?

- The first major difference between ESX & ESXi is that ESXi has no service console, which means that you can't execute any commands on the local console of the machine like its possible with ESX. Please note there is a smaller subset of commands that can be executed against the ESXi remotely using "Remote CLI", which is sufficient for most users. To be honest if you are an expert in VMware ESX, then you will know there is a very tiny unsupported console on the ESXi which meant to be only used by VMware support.

- As VMware ESXi has no service console, the size of it shrinks dramatically. In addition it will require way less patching than the normal version. Remember the Service console is running a stripped out version of Redhat which will require way more patches than the VMware kernel it self, so by getting rid of that you can save a lot of the time on getting updates.

- VMware ESXi was originally meant to be distribute as a very small image, which get to be preinstalled by your hardware vendor on a small flash memory drive (or solid state drive as in ESXi 3 the size is less than 32MB & in vSphere its less than 100MB in total. Though now VMware ESXi is available to be installed by the user, as long its supported on your particular server by your Hardware vendor.

- Please note the free VMware ESXi server includes the file system and functionality, VMFS, VMware Virtual SMP (symmetric multiprocessing) - which is the ability to configure more than one virtual CPU per VM, but in order to run advanced functionality such as VMotion, DRS, HA, Storage VMotion, FT you will require an additional license. If you need a basic & reliable Virtualization platform then the free ESXi can do the job for you, & when you decide to grow up & you require more advanced features you will only have to acquire the feature license and enable it in ESXi. In the other hand, VMware ESX has no free version offered & you will have to purchase a license to start using it. Please note the minimum license of VMware ESX has plenty more features than what is enabled on the Free ESXi before adding any license to ESXi. Though you always can obtain a license for the VMware ESXi & run all the features supported by VMware ESX without reinstalling anything.

- Please note when you obtain the free VMware ESXi, it will not include any official support till you obtain a license. This means if you are keeping the free VMware ESXi you will have to depend on the community support till you obtain a license which enable many features as said earlier. Its worth mentioning though the VMware community is very helpful.

So again you might be asking yourself when to use VMware ESXi & when to use VMware ESX?

Which one is the right solution for my environment is it VMware ESXi or VMware ESX?