Use the fault tolerance function with DRS

enabled Enhanced VMotion Compatibility(EVC) feature, you can Vspherefault tolerance with vSphere distributed Used with Resource Scheduler(DRS). This process allows fault-tolerant virtual machines to benefit from better initial drop locations and can also be included in the load-balancing calculations of the cluster.

when the cluster is enabled EVC ,DRS will propose initial placement locations for fault-tolerant virtual machines, move these VMS during the rebalance of the cluster load, and run the primary virtual machine to assign the DRS Automation level (the secondary virtual machine always takes the same settings as the primary virtual machine associated with it).

during initial placement or load balancing, the number of primary or secondary virtual machines that DRS places on the host does not exceed a fixed number. This limit is controlled by the advanced option das.maxftvmsperhost . The default value for this option is 4. However, if you set this option to 0,DRS ignores this limit.

when VSphere Fault tolerance is used for a virtual machine in a cluster that has EVC disabled, the DRS Automation level "disabled" is specified for fault-tolerant virtual machines . In this cluster, each primary virtual machine only turns on the power on its registered host, its secondary virtual machine is automatically placed, and the primary or secondary fault-tolerant virtual machine is not moved for load balancing.

if affinity rules are used for a pair of fault-tolerant virtual machines, the virtual machine- virtual machine affinity rule applies only to the primary virtual machine, while the virtual machine - host affinity rule applies to the primary virtual machine and its secondary virtual machines. If the virtual machine- virtual machine rule is set for the primary virtual machine, DRS attempts to resolve any conflicts that occur after the failover (that is, when the primary virtual machine is moved to a new host).

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Use the fault tolerance function with DRS