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
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VM-Host affinity rules place specified virtual machines on a particular host or a member of a defined
group of hosts during failover actions.
When you edit a DRS affinity rule, you must use vSphere HA advanced options to enforce the desired
failover behavior for vSphere HA.
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HA must respect VM anti-affinity rules during failover -- When the advanced option for VM anti-
affinity rules is set, vSphere HA does not fail over a virtual machine if doing so violates a rule.
Instead, vSphere HA issues an event reporting there are insufficient resources to perform the failover.
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HA should respect VM to Host affinity rules during failover --vSphere HA attempts to place VMs
with this rule on the specified hosts if at all possible.
For more information, see vSphere HA Advanced Options.
Note vSphere HA can restart a VM in a DRS-disabled cluster, overriding a VM-Host affinity rules
mapping if the host failure happens soon (by default, within 5 minutes) after setting the rule.
Other vSphere HA Interoperability Issues
To use vSphere HA, you must be aware of the following additional interoperability issues.
VM Component Protection
VM Component Protection (VMCP) has the following interoperability issues and limitations:
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VMCP does not support vSphere Fault Tolerance. If VMCP is enabled for a cluster using Fault
Tolerance, the affected FT virtual machines will automatically receive overrides that disable VMCP.
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VMCP does not detect or respond to accessibility issues for files located on vSAN datastores. If a
virtual machine's configuration and VMDK files are located only on vSAN datastores, they are not
protected by VMCP.
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VMCP does not detect or respond to accessibility issues for files located on Virtual Volume
datastores. If a virtual machine's configuration and VMDK files are located only on Virtual Volume
datastores, they are not protected by VMCP.
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VMCP does not protect against inaccessible Raw Device Mapping (RDM)s.
IPv6
vSphere HA can be used with IPv6 network configurations, which are fully supported if the following
considerations are observed:
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The cluster contains only ESXi 6.0 or later hosts.
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The management network for all hosts in the cluster must be configured with the same IP version,
either IPv6 or IPv4. vSphere HA clusters cannot contain both types of networking configuration.
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The network isolation addresses used by vSphere HA must match the IP version used by the cluster
for its management network.
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IPv6 cannot be used in vSphere HA clusters that also utilize vSAN.
vSphere Availability
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