VxRail virtual machines are made up of a set of objects. For example, a VMDK is an object, a snapshot is an object, VM swap space is an object, and the VM home namespace (where the .vmx file, log files, and so on are stored) is also an object. See the figure below.
Figure 43. vSAN objects and components
Virtual-machine objects are split into multiple components based on performance and availability requirements defined in the storage policy applied to the objects of the VM. For example, if the VM is deployed with a policy to tolerate a single failure, the objects have two replica components. Distributed storage uses a disk-striping process to distribute data blocks across multiple devices. The stripe itself refers to a slice of data; the striped device is the individual drive that holds the stripe. If the policy contains a stripe width, the object is striped across multiple devices in the capacity layer, and each stripe is an object component.
Each vSAN host has a maximum of 9,000 components. The largest component size is 255GB. For objects greater than 255GB, vSAN automatically divides them into multiple components. For example, a VMDK of 62TB generates more than 500 x 255GB components. The figure above illustrates how components that make up VM objects are spread across drive on nodes based on Failure to tolerate policy.