A Comparison of ESXi vs. ESX: What’s the Difference

A Comparison of ESXi vs. ESX: What’s the Difference

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There was a long debate when everyone was asked to give their statement about the difference between ESXi and ESX. Most administrators would ask this question during interviews and ask new VMware virtualization students.

Although ESX is no longer available, we thought it would be helpful, especially for new administrators, to understand the architectural difference between VMware ESXi and ESX.

Since VMware covers 3/4 of the global server virtualization market, it would not be wrong to call it the uncontested moderator in server virtualization. VMware enables virtualization most cost-effectively, even when the virtualization is resource-intensive.

No matter the kind of VMware software you use, ESX vs. ESXi is always a hotly debated topic. Whether you are just starting with VMware or have been using it for a long time, you will come across these terminologies sooner or later.

Making the correct choice between ESX versus ESXi is critical when considering virtual. Your success will rely on how competently you choose and install the correct version of VMware in your data center.

The two versions differ in performance, memory usage, and storage space.

What is VMware ESX

ESX (Elastic Sky X) is a VMware enterprise server virtualization platform. In ESX, VMkernel is the virtualization kernel that runs the console operating system, also called the service console.

It is Linux-based, and its primary purpose is to provide a management interface for the host, many management agents, and other third-party software agents installed on the service console.

It is enabled to provide functionalities such as hardware management and monitoring of the ESX hypervisor. ESX Server and ESX host are eligible with the VMware hypervisor architecture.

VMware ESX is a type 1 bare-metal hypervisor embedded between physical hardware and operating system and is used to develop and run virtual machines by directly invoking physical hardware resources.

Features of VMware ESX

  • High-level efficiency;
  • Reduction of cooling and energy costs;
  • Reduce the overall hardware footprint of an industry;
  • Secure and trusted server virtualization environment.

What is VMware ESXi

ESXi (Elastic sky X Integrated) is VMware’s business server virtualization platform. In ESXi, the service console has been removed. VMware-related agents and third parties, such as management and monitoring agents, can also work directly on VMkernel.

ESXi is an ultra-thin architecture that is highly trusted, and its small code base allows it to be more secure with fewer patch codes. ESXi uses the Direct Console User Interface (DCUI) instead of the ESXi Server Management Service Console.

ESXi installation will happen very quickly compared to ESX installation. The effectiveness and performance of VMware ESX and ESXi are very similar, not to say identical. The difference between them lies in their packaging architecture and operative management.

VMware ESXi substitutes the service console with a more integrated Direct Console (DCUI) user interface. The VMware ESXi is also a company-class Type 1 hypervisor.

Features of VMware ESXi

  • Lighter design with a small code base;
  • Control scripting environments;
  • Remote access tools;
  • API integration eradicates the need for administrators to install and handle third-party control agents;
  • Easy installation via USB flash drive;
  • Lightweight, protective configurations.

ESXi vs. ESX

VMware ESX and ESXi are functionally similar. What sets them apart is their packaging architecture and operational management. The critical difference between them is that the ESX architecture relies on a Linux-based console operating system (COS), while the ESXi architecture runs without COS.

In general, both are similar in terms of functionalities. What sets them apart is their architecture and operations management. That makes VMware ESXi more secure, boot space, and time manageable flexibly.

ESXi should be your choice to help you understand or decide which one to use for better security, confidentiality, and management, as it has a clear advantage in these departments. Also, ESX does not rely on any operating system.

If we are talking about VMware recommendations, then you should migrate from ESX to ESXi because that is what they recommend to users. It is a great way to get the most out of their hypervisor.

Critical differences

  • Smaller footprint: “Footprint” adheres to the amount of memory the software takes up. ESXi can be noticed as a scaled-down version of ESX;
  • Saving storage space: ESXi can take advantage of VMFS-5 volumes (larger than 2 TB), while ESX can not;
  • Flexible configuration models: VMware ESXi can now accept applications of almost any size, allowing customers to specify recommended configuration restrictions for a particular product;
  • User-friendly experience: One of the significant improvements is on the user experience side. Version 6.5 came with its vSphere client in HTML5 version. In particular, it is responsible for improving the user experience. Another helpful feature is the inclusion of CLI in vSphere, which allows users to give basic commands to the system, given that the machine from which knowledge is generated has access to the system. It also allows the use of a rest API for development tasks. This feature has optimized application security, conditional access, and more. A vSphere hypervisor is what ESXi stands for.
  • The ESXi architecture is more secure because the number of components included is lower than in ESX. ESXi also offers more tools and features for better infrastructure monitoring;
  • Rich ecosystem: Hardware, products, guest operating systems, and third-party services are supported by the VMware ecosystem. You can use third-party management software with your ESXi host, for example, to make infrastructure administration much more accessible or to back up your VMware ESXi VM image level at an affordable price.


The two supervisors are comparable in performance and reliability, at least when evaluating 4.1 releases. Yet, they are pretty different in terms of management structure and efficiency.

Unlike ESX, ESXi does not depend on the underlying operating system, allowing you to troubleshoot various performance and security issues.

VMware urges users to migrate to ESXi design; according to their literature, the process will take place without interruption of the VM, although it requires careful planning.

Because ESXi does not rely on a general-purpose operating system, unlike ESX, this allows you to solve several security and confidentiality issues.

VMware encourages migration to ESXi architecture; according to their documentation, migration can be performed without interrupting the VM, although the process requires careful preparation.