What’s New vSphere 6.5 – Host and Cluster Management

vSphere 6.5 brings new enhancements to ESXi hosts making administrator lives more easy. As discussed already integrated VUM has lot many advantages and you can just imagine what all headache it saves from like DB dependencies, availability issues and many more.  

Host Profiles is a very useful feature for larger environments and 6.5 has introduced many changes to it like ability to create hierarchy of host profiles. All the settings that you want to configure on host, popularly called as Host customization can be done from the values exported to a csv file and also checking Host Profile compliance is easier now with side by side comparison.


Auto Deploy in vSphere 6.5 now has a GUI and all those things that were done using command line are easy to do now.

Proactive HA

Using the hardware monitoring of a host, Proactive HA detects the host issues and evacuates the VMs on it. When changes are detected on the fans, power supplies or memory etc., we can now configure how hosts behave. A new mode called Quarantined Mode is introduced in vSphere 6.5 which is enabled on host when a Proactive HA is configured and hardware issues are detected. When a host is in Quarantine mode, DRS does not use this host for placement of virtual machines. Further to this Proactive HA can put the host in maintenance mode based on the severity of failure causing the VM to move to another host.

HA Orchestrated Restart

Remember how VMs are restarted in SRM at the recovery site during a recovery? Yeah, the VMs in HA cluster can also be configured to restart in a similar kind of style. We have dependency rules introduced in vSphere 6, with 6.5 two new rules have been introduced as Highest and Lowest to provide more granular control on the VMs.

HA Admission Control

Admission control is used to set aside a calculated amount of resources that are used when a host failure occurs. With vSphere 6.5, administrator can define Admission control by just specifying the number of host failures a cluster can tolerate. This is the default configuration and can be override. Once this has been set, HA automatically calculates the percentage of resources to set aside by applying the ‘Cluster Resource Percentage’ policy. When a new host is added or removed, the percentage is recalculated. Also, it is now possible to configure the performance loss that can be tolerated before a warning is appeared on the webclient.

Fault Tolerance

vSphere 6.5 FT has more integration with DRS helping to make better placement decisions by ranking the hosts based on the available network bandwidth and datastore to place the secondary vmdk. FT networks can now be configured to use multiple NICs to increase bandwidth available for logging traffic.

DRS Additional Options

Advanced options for DRS in earlier versions of vSphere now have a GUI based configuration settings. They can just be enabled and disabled using the check box.


VM Distribution – Enforces an even count of VMs spread across the hosts.

Memory Metric for Load Balancing – DRS uses Active memory + 25% as its primary metric when calculating memory load on a host. The Consumed memory vs active memory will cause DRS to use the consumed memory metric rather than Active.  This is beneficial when memory is not over-allocated.  As a side effect, the UI show the hosts be more balanced.

CPU over-commitment – This option enforces a maximum vCPU to pCPU ratio and once this is met, no VMs can be powered on.

Hope this was informative. Thanks!

©Pic Courtesy : VMware Press



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