By Alison / Last Updated December 2, 2022

Introduction to VMware vSphere, vCenter, and ESXi

VMware is undoubtedly the leading enterprise in virtualization. However, if you are not familiar with it, you may be confused by VMware’s so many products.

For example, VMware's popular product vSphere suite, vCenter Server, and the type-1 hypervisor ESXi. Do you know what are they, and what they can do respectively? What’s the difference between vSphere vs vCenter? And what’s the difference between vCenter and ESXi? And VMware vSphere vs ESXi?

In this article, I will answer these questions as simple as possible.

vSphere vs vCenter vs ESXi

This article covers the following contents:

What is VMware vSphere

In fact, what we call vSphere is not a specific software. VMware vSphere is a Server virtualization software suite of VMware that includes many software components. Each of them performs a different function in the vSphere environment.

The 2 core components of VMware vSphere are VMware ESXi and VMware vCenter Server.

Updated: VMware just released the stable new version of vSphere 8.0 on October 11, 2022. The new vSphere 8.0 supports up to 8 vGPUs per VM – a 2x increase compared to vSphere 7 U3, allowing you to run more and more powerful virtual machines, and perform tasks faster. You can upgrade to ESXi 8 and vCenter 8 to enjoy new vSphere 8 features.

upgrade to esxi 8

What is included in VMware vSphere

  • VMware ESXi
  • VMware vCenter Server
  • vCenter Single Sign-On
  • Security Token Service (STS)
  • Administration server
  • vCenter Lookup Service
  • VMware Directory Service
  • vCenter Server plug-ins
  • vCenter Server database
  • tcServer
  • vCenter Server agent
  • Host agent

For more introduction of these components of vSphere, you can refer to VMware’s official document: vSphere Software Components

What is VMware ESXi

VMware ESXi (formerly ESX) is an enterprise-class, type-1 hypervisor that is used to deploy and manage virtual machines. It is a special software installed directly on the bare metal, providing a virtual layer inserted between the bare metal and the operating system.

Without ESXi, you cannot virtualize anything, but without vCenter Server, you still got a VMware ESXi free edition which allows basic creating and running of virtual machines. Therefore, VMware ESXi is the most important part of vSphere suite.

VMware ESXi web client

VMware ESXi is one of the smallest hypervisors that can be quickly installed and booted. You can install ESXi from USB, CD/DVD, PXE, or remote management applications.

What is VMware vCenter Server

VMware vCenter Server is advanced server management software that provides a centralized platform for controlling your VMware vSphere environments, allowing you to automate and deliver a virtual infrastructure across the hybrid cloud.

The vCenter Server architecture consists of the following components:

  • vSphere Client and vSphere Web Client: used to manage your vCenter Server.
  • vCenter Server Database: stores the inventory items, security roles, resource pools, performance data, and other information. Support Oracle, and Microsoft SQL Server databases.
  • vCenter Single Sign-On (SSO): allows authentication against multiple user repositories, such as Active Directory or Open LDAP.
  • Managed hosts: ESXi hosts and their respective virtual machines.

VMware vCenter Server

You can have multiple vCenter Servers, up to 10 per SSO Domain. And a single vCenter Server instance can support a maximum of 1,000 hosts, 10,000 powered-on virtual machines and 15,000 registered virtual machines.

However, it doesn't provide the virtual machine backup feature. Therefore, to protect these VMs, you may need a backup software that capable of batch backup a large number of VMs.

VMware vSphere vs vCenter Server vs ESXi

Now you know what VMware vSphere, vCenter Server, and ESXi are and used for. In general, vSphere = ESXi + vCenter Server + something else.

VMware Logo

Here is a table that summarizes the difference between vCenter and ESXi, vSphere.

  vSphere ESXi vCenter Server
What it is VMware’s server virtualization suite Type-1 hypervisor installed on bare-metal Advanced server management software installed on the host
What it provides A complete infrastructure for virtualization Virtualization layer A centralized and extensible platform
What it is for Modern applications using any combination of VMs, containers, and Kubernetes Deploying and serving VMs Controlling VMware vSphere environments
Allows IT teams to Build a reliable and resilient infrastructure Create and manage multiple VMs Automate and deliver a virtual infrastructure across the hybrid cloud

Backup vSphere VMs managed by vCenter or Standalone ESXi

In addition to various kinds of products, VMware offers different levels of license for features. Sometimes, licenses can be really expensive for some advanced features, such as migration, replication, etc.

However, a standard backup feature is not included either on the free ESXi, or on vCenter. Therefore, when it comes to VM data protection, if you want a cost-effective solution, you will need choose specialized virtual machine backup solution. And if you use the free ESXi, you need to get additional support since it does not support vStorage APIs.

Here I introduce you an efficient VMware backup software - AOMEI Cyber Backup. It supports both paid and free versions of VMware ESXi, and offers you the following benefits.

Image-level VM Backup: independent image-level VM backups can be used to create new VMs.
Flexible vSphere Backup: batch backup numerous VMs managed by vCenter Server, or multiple VMs on a standalone ESXi host.
Automated Execution: create backup schedules to automate virtual machine protection.
Restore Entire VM: restore immediately available VMs from any selected restore points.

AOMEI Cyber Backup supports VMware vSphere/ESXi 6.0 and later versions. Next, I will demonstrate how to perform backup of multiple VMware ESXi VMs, either in standalone host or managed by vCenter Server. Click the following button to download the free trial.

Download Free TrialVMware 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 VMs in VMware vSphere 

1. Bind Devices: Access AOMEI Cyber Backup web client, navigate to Source Device > VMware > + Add VMware Device to Add vCenter or Standalone ESXi, 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, select the Backup Method as VMware ESXi Backup, then you can configure the Task Name, Device, Target, Schedule, and Backup Cleanup.

Create a VMware ESXi backup task

  • Device: you can select multiple VMs from added vCenter Server or standalone ESXi host.

Select virtual machines vCenter

  • 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 (optional): perform full, differential, or incremental backup, and automate execution according to the frequency you specified.

Backup schedule type

  • Cleanup (optional): automatically delete the old backup copies that exceed the retention period 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 setting. When you want to restore from a backup, you can choose to Restore to original location or Restore to new location.

By selecting the second option, you can 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

Summary

As VMware vSphere ESXi is one of the most popular hypervisors, you may want to get a general understanding of its complex products and features.

In this article I introduced what VMware vSphere, ESXi, vCenter Server are, what are they used for, and the difference between vSphere vs vCenter vs ESXi. After this, to decide which edition you want to start with, you can also refer to vSphere edition comparison.