I wanted to cover real quick creating a custom storage policy on vSAN, which even on a VxRail is done in vCenter.
House keeping items:
Raid 1 mirror is where you write a complete replica of the object. This is the highest performance protection you can apply to an object. Since it is a complete replica it consumes 100% additional storage, IE, a 100GB VMDK will consume 200GB storage space.
Raid 5 is where you can tolerate 1 failure leveraging distributed parity. This is considered a capacity saver because it requires 33% overhead as compared to the 100% of Raid 1. If you have the same 100GB object it will only consume 133GB.
Raid 6 is where you can tolerate 2 failures leveraging distributed parity. This is also considered a capacity saver as it only adds 50% overhead as compared to the 100% of Raid 1. If you have the same 100GB object it will only consume 150GB.
That is how simple it is to create a new storage policy that can be applied to objects in your environment.