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
Problem
When you attempt to power on a virtual machine with Fault Tolerance enabled, an error message might
appear if you did not enable HV.
Cause
This error is often the result of HV not being available on the ESXi server on which you are attempting to
power on the virtual machine. HV might not be available either because it is not supported by the ESXi
server hardware or because HV is not enabled in the BIOS.
Solution
If the ESXi server hardware supports HV, but HV is not currently enabled, enable HV in the BIOS on that
server. The process for enabling HV varies among BIOSes. See the documentation for your hosts'
BIOSes for details on how to enable HV.
If the ESXi server hardware does not support HV, switch to hardware that uses processors that support
Fault Tolerance.
Compatible Hosts Not Available for Secondary VM
If you power on a virtual machine with Fault Tolerance enabled and no compatible hosts are available for
its Secondary VM, you might receive an error message.
Problem
You might encounter the following error message:
Secondary VM could not be powered on as there are no compatible hosts that can accommodate it.
Cause
This can occur for a variety of reasons including that there are no other hosts in the cluster, there are no
other hosts with HV enabled, Hardware MMU Virtualization is not supported by host CPUs, data stores
are inaccessible, there is no available capacity, or hosts are in maintenance mode.
Solution
If there are insufficient hosts, add more hosts to the cluster. If there are hosts in the cluster, ensure they
support HV and that HV is enabled. The process for enabling HV varies among BIOSes. See the
documentation for your hosts' BIOSes for details on how to enable HV. Check that hosts have sufficient
capacity and that they are not in maintenance mode.
Secondary VM on Overcommitted Host Degrades Performance of
Primary VM
If a Primary VM appears to be executing slowly, even though its host is lightly loaded and retains idle
CPU time, check the host where the Secondary VM is running to see if it is heavily loaded.
vSphere Availability
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