An administrator creates a DRS cluster of eight ESXi 6.x hosts. There are 10 virtual machines balanced across the hosts. An attempt to place the first host into
maintenance mode fails.
What are two reasons that the host failed to enter maintenance mode? (Choose two.)

A.
The DRS cluster Automation Level is set to Partially Automated mode.

B.
One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Should run on hosts in group.

C.
One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Must run on hosts in group.

D.
One of the virtual machines on the ESXi Host entering maintenance mode is configured with an individual Automation Level set to Partially Automated.

Explanation:
When considering an automation level, it is usually best to choose Fully Automated and let DRS handle everything. However, when first enabling DRS, you might
want to set the automation level to Manual or Partially Automated so that you can observe its recommendations for a while before turning it loose on Fully
Automated. Even when selecting Fully Automated, you can still configure individual VM automation levels, so you can specify certain VMs to not be migrated at all
(disabled) or to be set to Manual or Partially Automated. To configure individual VM automation levels, click on Virtual Machine Options, located under DRS.
Usually, the default three-star level is a good starting point and works well for most environments. You should be careful when choosing more aggressive levels, as
you could have VMs moving very frequently between hosts (i.e., VM pong), which can create performance issues because of the constant VMotions which cause an

entire LUN to be locked during the operation (i.e., SCSI reservations).
http://cdn.ttgtmedia.com/searchSystemsChannel/downloads/AdvancedvSpherefeatures.pdf