It is usefull if you are going to create a Windows Cluster. In that case you have to create a quorum disk.
- enable remote console access to your ESXi host
- start putty
- go to your datastore (e.g. cd /vmfs/volumes/datastore1)
- mkdir CLUSTER
- cd CLUSTER
- vmkfstools –c 4G –d eagerzeroedthick –a lsilogic quorum.vmdk