This post is from my website Difference between VMware ESX and ESXi ~ VMware Arena


It's been a long debate that everyone has been asked by what is the difference between ESX and ESXi. Most of the admins would have asked this question during interviews and also asked by new learners of VMware virtualization. I decided to post on the topic to give architectural difference always as to compare the different level capabilities between ESX & ESXi.
What is VMware ESX ?

ESX (Elastic Sky X) is the VMware’s enterprise server virtualization platform. In ESX, VMkernel is the virtualization kernel which is managed by a console operating system which is also called as Service console. Which is linux based and its main purpose is it to provide a Management interface for the host and lot of management agents and other thrid party software agents are installed on the service console to provide  the functionalists like hardware management and monitoring of ESX hypervisor.                                                                                                                                        

Graphic Thanks to VMware



What is VMware ESXi ?

ESXi (Elastic sky X Integrated) is also the VMware’s enterprise server virtualization platform. In ESXi, Service console is removed. All the VMware related agents and third party agents such as management and monitoring agents can also run directly on the VMkernel. ESXi is ultra-thin architecture which is highly reliable and its small code-base allows it to be more secure with less codes to patch. ESXi uses Direct Console User Interface (DCUI) instead of a service console to perform management of ESXi server. ESXi installation will happen very quickly as compared to ESX installation.


Graphic Thanks to VMware


Difference between ESX and ESXi

ESX 4.1 is the last version availability of ESX server. After vSphere 5, only ESXi is available.  This comparison based out of the VMware Article

CapabilityESX     ESXi
Service ConsolePresentRemoved
Troubleshooting performed viaService Console            ESXi Shell
Active Director AuthenticationEnabledEnabled
Secure SyslogNot SupportedSupported
Management NetworkService Console InterfaceVMKernel Interface
Jumbo FramesSupportedSupported
Hardware Montioring3 rd Party agents installed in Service consoleVia CIM Providers
Boot from SANSupported in ESXSupported in ESXi
Software patches and updatesNeeded as smilar to linux operation systemFew pacthes because of small footprint and more secure
vSphere web AccessOnly experimentalFull managenet capability via vSPhere web client
Locked Down ModeNot presentPresent . Lockdown mode prevents remote users to login to the host
Scripted InstalltionSupportedSupported
vMA SupportYesYes
Major Administration command-line Commandesxcfg-esxcli
Rapid deployment via Auto DeployNot supportedSupported
Custom Image creationNot supportedSupported
VMkernel Network Used forvMotion,Fault Tolarance,Stoarge ConnectivityManagement Network , vMotion, Fault Tolarance, Stoarge Connectivity, ISCSI port binding