6.7
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
- How Fault Tolerance Works
- Fault Tolerance Use Cases
- Fault Tolerance Requirements, Limits, and Licensing
- Fault Tolerance Interoperability
- Preparing Your Cluster and Hosts for Fault Tolerance
- Using Fault Tolerance
- Best Practices for Fault Tolerance
- Legacy Fault Tolerance
- Troubleshooting Fault Tolerant Virtual Machines
- Hardware Virtualization Not Enabled
- Compatible Hosts Not Available for Secondary VM
- Secondary VM on Overcommitted Host Degrades Performance of Primary VM
- Increased Network Latency Observed in FT Virtual Machines
- Some Hosts Are Overloaded with FT Virtual Machines
- Losing Access to FT Metadata Datastore
- Turning On vSphere FT for Powered-On VM Fails
- FT Virtual Machines not Placed or Evacuated by vSphere DRS
- Fault Tolerant Virtual Machine Failovers
- 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
In a partitioned vSphere HA cluster using Fault Tolerance, the Primary VM (or its Secondary VM) could
end up in a partition managed by a master host that is not responsible for the virtual machine. When a
failover is needed, a Secondary VM is restarted only if the Primary VM was in a partition managed by the
master host responsible for it.
To ensure that your management network is less likely to have a failure that leads to a network partition,
follow the recommendations in Best Practices for Networking.
Using vSAN Datastores
vSphere Fault Tolerance can use vSAN datastores, but you must observe the following restrictions:
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A mix of vSAN and other types of datastores is not supported for both Primary VMs and Secondary
VMs.
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vSAN metro clusters are not supported with FT.
To increase performance and reliability when using FT with vSAN, the following conditions are also
recommended.
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vSAN and FT should use separate networks.
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Keep Primary and Secondary VMs in separate vSAN fault domains.
Legacy Fault Tolerance
Legacy FT VMs can exist only on ESXi hosts that are running on vSphere versions earlier than 6.5.
ESXi hosts prior to version 6.5 supported vSphere Fault Tolerance based on a different technology. If you
are using this form of Fault Tolerance and need to continue doing so, we recommend you reserve a
vCenter 6.0 instance to manage the pool of pre-6.5 hosts required to run these VMs. vCenter 6.0 was the
last version fully capable of managing legacy FT protected VMs. For more information on Legacy Fault
Tolerance, see vSphere Availability 6.0 documentation.
Troubleshooting Fault Tolerant Virtual Machines
To maintain a high level of performance and stability for your fault tolerant virtual machines and also to
minimize failover rates, you should be aware of certain troubleshooting issues.
The troubleshooting topics discussed focus on problems that you might encounter when using the
vSphere Fault Tolerance feature on your virtual machines. The topics also describe how to resolve
problems.
You can also see the VMware knowledge base article at http://kb.vmware.com/kb/1033634 to help you
troubleshoot Fault Tolerance. This article contains a list of error messages that you might encounter when
you attempt to use the feature and, where applicable, advice on how to resolve each error.
Hardware Virtualization Not Enabled
You must enable Hardware Virtualization (HV) before you use vSphere Fault Tolerance.
vSphere Availability
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