Note: The Atomic Test and Set (ATS) primitive is used for locking on Virtual Machine File System (VMFS) datastores for VMware vSphere Storage APIs for Array Integration (VAAI) compatible storage arrays. It is far superior to the SCSI Reservation locking technique. For more information on VAAI, see Frequently Asked Questions for vStorage APIs for Array Integration (1021976).
There are two main categories of operation under which VMFS makes use of SCSI reservations.
These are some examples of VMFS operations that require locking metadata:
6.
Note: Use of SATA disks is not recommended in high I/O configuration or when the above changes do not resolve the problem while SATA disks are used.