VMware's Fault Tolerance (FT) and High Availability (HA) are both focused on uptime and keeping
virtual machines running. Once a company determines its uptime and data recovery needs, it can
decide whether High Availability or Fault Tolerance is the better choice.
While Fault Tolerance is a high availability feature that can be used in a VMware HA cluster, there are meaningful differences between the two. Each requires a setup with different available resources and both have a different effect on virtual machines.
The resources presented in this guide to VMware FT and HA will help you understand your options with some real-world use cases to compare to your IT infrastructure and needs.
1How uptime features compare-
The key difference between VMware's High Availability and Fault Tolerance offerings is the interruption to virtual machines in the event of a host failure. Fault Tolerance eliminates downtime -- even when hardware founders -- by keeping a copy of a critical virtual machine (VM) on another host. For VMs protected by High Availability, if the host running the VM fails, then the VM will get restarted on another server; if the VM fails because of an operating system crash, HA will restart the VM on the same host.
2What's needed to run FT and HA-
It's important to differentiate how High Availability and Fault Tolerance operate. If you can't afford to have interruption, Fault Tolerance instantly gets to work after a host failure. HA can get virtual machines back up and running with very little disturbance.
Without the option to purchase vCenter Server Heartbeat, administrators seeking high availability for vCenter Server have to weigh their options, which may include new choices down the road. Continue Reading
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3How they work-
Using High Availability and Fault Tolerance
Now that you know what Fault Tolerance and High Availability are, it's time to focus on them in action. These real-world scenarios for implementation will help you to better understand how and why to use either tool.
Traditional high-availability architectures rely on expensive shared storage and premium hypervisor features, but sometimes you can save money by scaling out instead of up. Continue Reading