VMware ESX vs ESXi Comparison: What’s the difference?

VMware ESXi was formerly known ESX, do you know when and why it renamed? In this article, I will introduce them respectively, and make a VMware ESX vs ESXi comparison.


By Crystal / Updated on March 8, 2023

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Is VMware ESXi same as ESX?

You may have heard of ESX and ESXi, both of them are VMware’s well-known type-1 hypervisors. vSphere 4.1 is the last version availability of ESX server. After vSphere 5, only ESXi is available. But is ESXi same as ESXi? What’s the difference between them?

In this article, I will introduce them respectively and compare the difference of VMware ESX vs ESXi.

VMware Logo

What is VMware ESX

ESX, originated as an abbreviation of Elastic Sky X, is VMware’s enterprise class virtualization tool. VMware ESX is a bare-metal type-1 hypervisor, inserted between the physical hardware and operating system, and used to create and run virtual machines by directly calling on physical hardware resources. It is managed by Service Console, an operating system that manages the virtualization kernel VMkernel.

VMware virtualization

The last version VMware released that includes ESX hypervisor architecture is vSphere 4.1, released in August 2010. After this, VMware announced the transition away from ESX, its classic hypervisor architecture, to ESXi, a more lightweight solution. ESXi became the replacement for ESX.

What is VMware ESXi

ESXi, which stands for Elastic Sky X Integrated, is VMware’s more advanced and integrated version of ESX. After released VMware ESX version 4.1 in 2010, VMware renamed ESX to ESXi.

VMware ESXi is also an enterprise class type-1 hypervisor. The functionality and performance of VMware ESX and ESXi are the same. The difference between them resides in their packaging architecture and operational management. For example. VMware ESXi replaces the Service Console with a more closely integrated Direct Console User Interface (DCUI).

VMware ESXi logo

VMware ESX vs ESXi: What’s the difference

VMware ESX and ESXi are functionally similar, what differentiate them is their packaging architecture and operational management. The most key difference between them is that the architecture of ESX relies on a Linux-based Console Operating System (COS), while the ESXi architecture operates without the COS. This makes VMware ESXi more secure, space and boot time effective, and flexible to manage.

  • Smaller footprint: “Footprint” refers to the amount of memory a software takes up. ESXi can be seen as a scaled-down version of ESX.
  • Storage space saving: ESXi can take advantage of VMFS-5 volumes (with space larger than 2 TB) while ESX cannot.
  • Flexible configuration models: VMware ESXi now has the ability to accommodate applications of virtually any scale, allows customers to determine the recommended configuration limitations for a certain product.
  • More Secure: ESXi architecture is more secure because the number of components involved in it has been decreased than in ESX. And ESXi offers more tools and features to better monitor infrastructure.
  • Rich ecosystem: Third-party hardware, products, guest operating systems, and services are all supported by the VMware ecosystem. You may utilize third-party management software in combination with your ESXi host, for example, to make infrastructure administration much easier, or backup VMware ESXi VMs at image-level with affordable price.

Although one instance of free VMware ESXi can be managed with the vSphere Client, the VMware ESXi free limitations are fatal. For example, it does not support vStorage APIs, therefore you may be limited when selecting backup solutions. More features need to be unlocked with other editions or licenses.

For more details about other editions, you can refer to vSphere edition comparison.

Free VMware ESXi VMs protection software – AOMEI Cyber Backup

The consequences of data loss can be devastating. Therefore, when you start using virtual machines, having a good virtual machine bakup schedule is your best data insurance.

However, native VMware backup solutions may insufficient or expensive for you. Therefore, you may need an effective software to backup VMware ESXi VMs. Here I introduce you to a free VMware backup software -- AOMEI Cyber Backup.

It supports both paid and free ESXi, and offers you the following benefits.

Image-level Multiple VM Backup: independent image-level VM backups can be used to create new VMs.
Automated Execution: create backup schedules to automate virtual machine protection.
Restore Entire VM: restore immediately available VMs from any selected restore points.
Perpetual Free: you can use AOMEI Cyber Backup Free Edition with no time limit.

AOMEI Cyber Backup supports VMware ESXi 6.0 and later versions. Next, I will demonstrate how to quickly create a complete backup task in 3 simple steps. You can click the button below to start your download the freeware.

Download FreewareVMware ESXi & Hyper-V
Secure Download

*You can choose to install this VM backup software on either Windows or Linux system.

3 simple steps to backup multiple VMware ESXi VMs

1. Bind Devices: Access AOMEI Cyber Backup web client, navigate to Source Device > VMware > + Add VMware Device to add vCenter or Standalone ESXi host as the source device, and then click > Bind Device.

Note: Once bound the host you do not need to repeat this step later.

Add VMware ESXi host

2. Create Backup Task: Navigate to Backup Task > + Create New Task, and then set the Task Name, Backup Type, Device, Target, and Schedule.

Create a VMware ESXi backup task

  • Device: cover multiple VMs on the host in one backup task.
  • Target: selecting to back up to a local path, or to a network path. Used paths will be saved in Favorite Storage for handy selection.
  • Schedule: performing full, differential or incremental backup, and automate execution daily, weekly or monthly according to the frequency you specified.

Backup schedule type

3. Start Backup: You can click Start Backup and select to Add the schedule and start backup now, or Add the schedule only.

Start Backup

Created backup tasks will be listed and monitored separately, for restoring, progress checking and schedule changing.

While the Free Edition covers most of VM backup needs, you can also upgrade to Premium Edition to enjoy:
Batch VM Backup: batch backup large numbers of VMs managed by vCenter Server or standalone ESXi hosts.
Backup cleanup: Configure a retention policy to auto delete old backup files and save storage space.
Restore to new location: Create a new VM in the same or another datastore/host directly from the backup, saves the trouble of re-configuring the new VM.

Restore to new location


You may not be familiar with VMware ESX or even haven’t heard of it since after vSphere 4.1, only ESXi is available. In this article, I introduced what is VMware ESX and ESXi respectively, and compared the difference of VMware ESX vs ESXi.

The functionality and performance of VMware ESX and ESXi are the same, what differentiate them are their packaging architecture and operational management. To centrally manage and backup your VMware ESXi VMs, you can try AOMEI Cyber Backup free!

Crystal · Editor
Crystal is an editor from AOMEI Technology. She mainly writes articles about virtual machine. She is a positive young lady likes to share articles with peolpe. Off work she loves travelling and cooking which is wonderful for life.