It does not actually participate in the data path, but it triggers data path operations and as such is a critical component during a number of management workflows and failure handling scenarios.
Virtual machine power on, or Storage vMotion to vSAN are two operations where CLOMD is required (and which are not that obvious), as those operations require the creation of a swap object, and object creation requires CLOMD.
Similarly, starting with vSAN 6.0, memory snapshots are maintained as objects, so taking a snapshot with memory state will also require the CLOMD.
EPD (Entry Persistence Daemon) is a user space daemon that runs on every host that is part of the vSAN cluster. The main job of EPD is to make sure there is no component leakage when objects are deleted.
CMMDSD (Cluster Monitoring, Membership, and Directory Service Daemon) is a daemon to persist CMMDS (Cluster Monitoring, Membership and Directory Service) directory contents. It loads CMMDS user world process and provides an interface to CMMDS. CMMDS is responsible for monitoring the links to the cluster, and acts as a primary distribution fabric for cluster metadata. It is also responsible for maintaining the state of cluster health and network links. Other modules use this information to know which nodes are part of the cluster and also which are the healthy interfaces for these nodes.
/etc/init.d/cmmdsd status && /etc/init.d/epd status && /etc/init.d/clomd status
If the daemon is not running, try run restart command on the ESXi host:
/etc/init.d/cmmdsd restart && /etc/init.d/epd restart && /etc/init.d/clomd restart
https://kb.vmware.com/s/article/2109873
