2.3.2 The Distributed Object Manager (DOM)
The DOM exists in kernel space and there are no daemons that can be monitored or restarted without booting the host. The DOM is responsible for handling object availability and initial I/O requests. In addition:
• All objects exist at the DOM layer.
• All I/O is directed to the DOM client.
• One DOM client per vSAN enabled ESXi host.
• I/O is forwarded to the DOM owner.
• One DOM owner per object.
• There is no concept of locality—the DOM owner might be a host that does not own any component of the object.
• The DOM owner can change.
• The DOM is responsible for ensuring that all sides of a mirror are consistent.
• The DOM handles the synchronous I/O.