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What are the major differences between ESX, KVM and QEMU?

Sasikiran Vaddi
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1 Answers1

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Qemu is an open source user-space virtual machine monitor. It uses binary translation to run the guest instructions.

Pros : 
1) Has support of helpers which help a lot in debugging
2) Can be used to run guest of a different ISA. (You can emulate an ARM guest on x86 desktop)
3) Does not need hardware support
4) code is available. you can modify it for debugging

Cons:

1) Slow

KVM is an open source virtual machine monitor which is implemented in the linux kernel. Qemu can run a guest on KVM using the /dev/kvm interface. 

Pros:
1) very fast
2) code is available in the kernel tree. you can modify it for debugging

Cons:
1) needs hardware support
2) Requires a user level software for interfacing (generally qemu)

VMX is a virtual machine monitor by VMWare. The source code of VMX is not freely available. But it supports both user space as well as hardware supported emulation.

Pros : 
1) Very easy to use. GUI is good.
2) Fast and configurable. 

Cons :
1) Cannot modify it to obtain more information about the guest.
prathmesh.kallurkar
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  • What about ESX? Is VMX is alias of ESX – Sasikiran Vaddi May 27 '12 at 06:02
  • Taken from http://blogs.vmware.com/vapp/2009/11/index.html. For VMware products we use the form ‘vmx-X’ where X is VMware's virtual hardware version number. The import process will convert the virtual hardware to use this version number. Several hardware versions may be defined by using space as a delimiter e.g. “vmx-04 vmx-07” – prathmesh.kallurkar May 27 '12 at 08:15
  • btw, if your question is answered you must accept the answer. – prathmesh.kallurkar May 27 '12 at 08:23
  • Thank you for the information which you have provided, it is so helpful to me. The hypervisor concept is entirely new to me, so inorder to clarify my doubt i asked the above question i.e., is VMX and ESX are same. I am not denying your answer Prathmesh, the reply which you have given has helped me a lot in getting into the hypervisors concept. Thank you. – Sasikiran Vaddi May 28 '12 at 04:29