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
availability of critical information. With vSphere Fault Tolerance, you can protect this virtual machine
before running this report and then turn off or suspend Fault Tolerance after the report has been
produced. You can use On-Demand Fault Tolerance to protect the virtual machine during a critical time
period and return the resources to normal during non-critical operation.
Fault Tolerance Requirements, Limits, and Licensing
Before using vSphere Fault Tolerance (FT), consider the high-level requirements, limits, and licensing that
apply to this feature.
Requirements
The following CPU and networking requirements apply to FT.
CPUs that are used in host machines for fault tolerant VMs must be compatible with vSphere vMotion.
Also, CPUs that support Hardware MMU virtualization (Intel EPT or AMD RVI) are required. The following
CPUs are supported.
n
Intel Sandy Bridge or later. Avoton is not supported.
n
AMD Bulldozer or later.
Use a 10-Gbit logging network for FT and verify that the network is low latency. A dedicated FT network is
highly recommended.
Limits
In a cluster configured to use Fault Tolerance, two limits are enforced independently.
das.maxftvmsperhost The maximum number of fault tolerant VMs allowed on a host in the cluster.
Both Primary VMs and Secondary VMs count toward this limit. The default
value is 4.
das.maxftvcpusperhost The maximum number of vCPUs aggregated across all fault tolerant VMs
on a host. vCPUs from both Primary VMs and Secondary VMs count
toward this limit. The default value is 8.
Licensing
The number of vCPUs supported by a single fault tolerant VM is limited by the level of licensing that you
have purchased for vSphere. Fault Tolerance is supported as follows:
n
vSphere Standard and Enterprise. Allows up to 2 vCPUs
n
vSphere Enterprise Plus. Allows up to 8 vCPUs
Note FT is only supported in vSphere Enterprise and vSphere Enterprise Plus Editions.
vSphere Availability
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