Tip

Understanding VMware Fault Tolerance benefits and requirements

VMware Fault Tolerance (FT) is a new high availability feature in VMware's vSphere 4. With Fault Tolerance, your virtual guest machine runs on a primary ESX host server while the memory of that virutual machine (VM) is mirrored (using vLockstep) over to a secondary (ghost) ESX host server. If the primary ESX Server fails, the virtual machine immediately resumes operation on the secondary ESX Server with zero downtime to the VM, application or end user using that VM.

The benefits of VMware Fault Tolerance
Unlike traditional high-availability (HA) technologies, VMware's Fault Tolerance works regardless of the operating system, and you aren't charged for every server that uses this HA feature. FT is based on VMware Workstation's Record/Replay features that can play back what happened in a VM.

Fault Tolerance is not used for load balancing - it is strictly for high availability of a VM in the event that an ESX Server goes down. Unlike VMware HA clusters (VMHA), with FT, the VM that was protected doesn't have to be rebooted. Thus, with FT, unlike VMHA, there is no downtime for end users.

VMWARE FEATURES AND PRODUCTS GUIDE:

VMware virtualization products and features overview

VMware vSphere features

VMware ESX features

VMware ESXi features

VMware VMotion and live migration

How VMware's Storage VMotion works

The benefits – and limits of VMware HA

VMware Consolidated Backup: When should you use it?

VMware vShield Zones VMware Fault Tolerance benefits and requirements

Using VMware Distributed Power Management

The best thing about VMware FT is that to enable it, all you need to do is to right-click on the primary VM and enable Fault Tolerance. At that point, FT takes over, creating the secondary VM that will protect the primary VM if the ESX server running the primary VM has a failure.

    Requires Free Membership to View

The hardware requirements for VMware Fault Tolerance
VMware FT requires Intel 31xx, 33xx, 52xx, 54xx, 55xx, 74xx or AMD 13xx,23xx, 83xx series of processors (or greater). Moreover, you can't run FT on just any vSphere-compatible server because FT uses special features of the CPU. Today, FT is also supported only on VMs that have a single CPU (no multiprocessor VMs can use FT).

High availability, in general, is an excellent part of any large scale disaster recovery strategy. With Fault Tolerance you have the added protection for smaller-scale disasters such as the loss of a single ESX host server running 50+ virtual machines.

VMware's Fault Tolerance (FT) is offered in 3 of the 6 vSphere Editions - Advanced, Enterprise and Enterprise Plus. Additionally, VMware's vCenter is required.

For more information, read all about Fault Tolerance at VMware's Fault Tolerance (FT) product page or watch a video demonstrating the power of FT over at VMware's YouTube FT Demo.

Return to guide's main page for more on VMware virtualization products and features

About the author
David Davis is the director of infrastructure at TrainSignal.com -- the global leader in video training for IT pros. He has several certifications including vExpert, VMware Certified Profession (or VCP), CISSP, and CCIE #9369. Additionally, Davis has authored hundreds of articles and six video training courses at Train Signal, where one of the most popular course is the VMware vSphere 4 video training course. His website is VMwareVideos.com. You can follow Davis on Twitter or connect with him on LinkedIn.


 

This was first published in November 2009

There are Comments. Add yours.

 
TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.