Which option, if any, is the default option to enable Maintenance Mode on a vSAN host?

A vSAN administrator is implementing deduplication and compression on a vSAN all-flash cluster but wants the VMs to remain operational. The details are as follows:
There are 4 nodes in the vSAN cluster.
Existing VMs use a RAID-5 storage policy.
Which action should the vSAN administrator take to meet this goal?

An organization wants to configure a new storage policy based on the following requirements:
Failures to tolerate = FTT 1/RAID-5 (Erasure Coding)
Number of disk stripes per object = 8
IOPS limit for object = 0
Object Space Reservation = Thin provisioning
Flash read cache reservation = 0%
Disable object checksum = No
Force provisioning = No
The administrator creates the policy using storage policy based management and assigns it to a 100GB virtual machine on a 4-node vSAN cluster to test the results of the new storage policy.
How many components will be created per host for the storage objects of the virtual machine on the vSAN datastore?

During yesterday's business hours, a cache drive failed on one of the vSAN nodes. The administrator reached out to the manufacturer and received a replacement drive the following day. When the drive failed, vSAN started a resync to ensure the health of data, and all objects are showing a healthy and compliant state. The vSAN administrator needs to replace the failed cache drive.
Which set of steps should the vSAN administrator take?

A vSAN administrator has recently upgraded a vSAN cluster to 7.0 U1 and has enabled Capacity Reserve features to reduce the amount of capacity reserved for transient and rebuild operations.
Which scenario would prevent this feature from operating properly?