6.5.1
Table Of Contents
- vSphere Availability
- Contents
- About vSphere Availability
- Business Continuity and Minimizing Downtime
- Creating and Using vSphere HA Clusters
- Providing Fault Tolerance for Virtual Machines
- vCenter High Availability
- Plan the vCenter HA Deployment
- Configure the Network
- Configure vCenter HA With the Basic Option
- Configure vCenter HA With the Advanced Option
- Manage the vCenter HA Configuration
- Set Up SNMP Traps
- Set Up Your Environment to Use Custom Certificates
- Manage vCenter HA SSH Keys
- Initiate a vCenter HA Failover
- Edit the vCenter HA Cluster Configuration
- Perform Backup and Restore Operations
- Remove a vCenter HA Configuration
- Reboot All vCenter HA Nodes
- Change the Appliance Environment
- Collecting Support Bundles for a vCenter HA Node
- Troubleshoot Your vCenter HA Environment
- Patching a vCenter High Availability Environment
- Using Microsoft Clustering Service for vCenter Server on Windows High Availability
- Index
Providing Fault Tolerance for Virtual
Machines 3
You can use vSphere Fault Tolerance for your virtual machines to ensure continuity with higher levels of
availability and data protection.
Fault Tolerance is built on the ESXi host platform, and it provides availability by having identical virtual
machines run on separate hosts.
To obtain the optimal results from Fault Tolerance you must be familiar with how it works, how to enable it
for your cluster, virtual machines and the best practices for its usage.
This chapter includes the following topics:
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“How Fault Tolerance Works,” on page 41
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“Fault Tolerance Use Cases,” on page 42
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“Fault Tolerance Requirements, Limits, and Licensing,” on page 42
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“Fault Tolerance Interoperability,” on page 43
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“Preparing Your Cluster and Hosts for Fault Tolerance,” on page 45
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“Using Fault Tolerance,” on page 47
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“Best Practices for Fault Tolerance,” on page 51
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“Legacy Fault Tolerance,” on page 53
How Fault Tolerance Works
You can use vSphere Fault Tolerance (FT) for most mission critical virtual machines. FT provides continuous
availability for such a virtual machine by creating and maintaining another VM that is identical and
continuously available to replace it in the event of a failover situation.
The protected virtual machine is called the Primary VM. The duplicate virtual machine, the Secondary VM,
is created and runs on another host. The Secondary VM's execution is identical to that of the Primary VM
and it can take over at any point without interruption, thereby providing fault tolerant protection.
The Primary and Secondary VMs continuously monitor the status of one another to ensure that Fault
Tolerance is maintained. A transparent failover occurs if the host running the Primary VM fails, in which
case the Secondary VM is immediately activated to replace the Primary VM. A new Secondary VM is started
and Fault Tolerance redundancy is reestablished automatically. If the host running the Secondary VM fails,
it is also immediately replaced. In either case, users experience no interruption in service and no loss of data.
VMware, Inc.
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