2V0-620 · Question #182
An administrator has been tasked with enabling High Availability (HA) on a cluster in a vSphere 6.x environment with default settings. The cluster configures properly and there are no errors. The next
The correct answer is C. The default slot size in the cluster is set too high. D. There are virtual machines with large CPU reservations. E. A host is in maintenance mode for a replacement of a failed Hard Drive.. The 'Not Enough Failover Resources' error in vSphere HA occurs when the cluster's slot-based admission control calculates insufficient capacity, often due to oversized slots, large reservations, or reduced host count.
Question
An administrator has been tasked with enabling High Availability (HA) on a cluster in a vSphere 6.x environment with default settings. The cluster configures properly and there are no errors. The next day when powering on a virtual machine, an error is presented:
Not Enough Failover Resources Which three scenarios are likely causes of this error message? (Choose three.)
Options
- AThe default VM Monitoring Sensitivity is set too high.
- BThere are not enough datastore heartbeat datastores configured by default.
- CThe default slot size in the cluster is set too high.
- DThere are virtual machines with large CPU reservations.
- EA host is in maintenance mode for a replacement of a failed Hard Drive.
How the community answered
(16 responses)- A19% (3)
- B38% (6)
- C44% (7)
Why each option
The 'Not Enough Failover Resources' error in vSphere HA occurs when the cluster's slot-based admission control calculates insufficient capacity, often due to oversized slots, large reservations, or reduced host count.
VM Monitoring Sensitivity controls the aggressiveness of restarting VMs that stop sending heartbeats - it does not affect admission control or the calculation of available failover slots.
Datastore heartbeat datastores are used for host isolation detection to distinguish a failed host from a network-isolated one; they have no role in determining whether sufficient failover capacity exists.
HA uses the largest CPU and memory reservation across all powered-on VMs to define a slot size; if this default slot size is inflated, fewer slots exist cluster-wide, causing admission control to block new VM power-ons.
Virtual machines with large CPU reservations directly increase the calculated slot size, which reduces the total number of available slots and can cause admission control to report insufficient failover resources.
A host in maintenance mode is removed from the pool of available HA resources; with fewer active hosts, the cluster may no longer satisfy the configured failover host count or percentage, triggering the error.
Concept tested: vSphere HA admission control slot calculation
Source: https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.avail.doc/GUID-FAFEFEFF-56F7-4CDF-A682-FC3C62A29A95.html
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