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
Several validation checks are performed on a virtual machine before Fault Tolerance can be turned on.
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SSL certificate checking must be enabled in the vCenter Server settings.
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The host must be in a vSphere HA cluster or a mixed vSphere HA and DRS cluster.
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The host must have ESXi 6.x or greater installed.
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The virtual machine must not have snapshots.
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The virtual machine must not be a template.
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The virtual machine must not have vSphere HA disabled.
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The virtual machine must not have a video device with 3D enabled.
Checks for Powered-On Virtual Machines
Several additional validation checks are performed for powered-on virtual machines (or those that are in
the process of being powered on).
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The BIOS of the hosts where the fault tolerant virtual machines reside must have Hardware
Virtualization (HV) enabled.
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The host that supports the Primary VM must have a processor that supports Fault Tolerance.
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Your hardware should be certified as compatible with Fault Tolerance. To confirm that it is, use the
VMware Compatibility Guide at http://www.vmware.com/resources/compatibility/search.php and
select Search by Fault Tolerant Compatible Sets.
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The configuration of the virtual machine must be valid for use with Fault Tolerance (for example, it
must not contain any unsupported devices).
Secondary VM Placement
When your effort to turn on Fault Tolerance for a virtual machine passes the validation checks, the
Secondary VM is created. The placement and immediate status of the Secondary VM depends upon
whether the Primary VM was powered-on or powered-off when you turned on Fault Tolerance.
If the Primary VM is powered on:
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The entire state of the Primary VM is copied and the Secondary VM is created, placed on a separate
compatible host, and powered on if it passes admission control.
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The Fault Tolerance Status displayed for the virtual machine is Protected.
If the Primary VM is powered off:
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The Secondary VM is immediately created and registered to a host in the cluster (it might be re-
registered to a more appropriate host when it is powered on.)
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The Secondary VM is not powered on until after the Primary VM is powered on.
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The Fault Tolerance Status displayed for the virtual machine is Not Protected, VM not Running.
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When you attempt to power on the Primary VM after Fault Tolerance has been turned on, the
additional validation checks listed above are performed.
vSphere Availability
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