Architecting VMware vSAN 6.2 : vSAN Design Overview : 5.6 vSAN Requirements : 5.6.5 vSAN Policy Design : 5.6.5.2 vSAN Default Policy
   
5.6.5.2 vSAN Default Policy
By default, policies are configured based on the application requirements. However, they are applied differently depending on the object. The following table lists the default policy options applied to the different objects in vSAN.
Table 9. Object Policy Defaults
Object
Policy
Comments
Virtual Machine Namespace
1 Failures-to-Tolerate
Configurable. However, changes are not recommended.
Swap
1 Failures-to-Tolerate
Configurable. However, changes are not recommended.
Virtual Disks
User-Configured Storage Policy
Can be any storage policy configured on the system.
Virtual Disk Snapshots
Uses Virtual Disk Policy
Same as Virtual Disk policy by default. Changing is not recommended.
 
If there is no user-configured policy, the default system policy of one failure-to-tolerate and one disk stripe is used for virtual disks and virtual disk snapshots.
Policy defaults for the VM namespace and swap are set statically and are not configurable, so that there is appropriate protection for these critical virtual machine components. Policies must be configured based on the application’s requirements. This feature gives vSAN its power, because it can adjust how a disk performs on demand based on the configured policies.