4.2.16 Do not cause errors on shared storage devices
In a cluster configuration, multiple devices may be connected to a shared storage. In such configurations, the UEFI driver should not cause errors that can be seen by the other devices that are connected to storage.
Caution: On a boot or reboot, there shall be no writes to shared storage without user acknowledgement. Any writes to shared storage by a UEFI driver may corrupt shared storage as viewed by another system. As a result, all outstanding I/O in the controller's buffers will be cleared, as well as any internal. Any I/O operations that occur after a reboot may corrupt shared storage.
Caution: There must not be an excessive number of bus or device resets. Device resets have an impact on shared storage as viewed by other systems. For a single reset, this impact is negligible. Larger numbers of resets may be seen as a device failure by another system.
Caution: Disk signatures must not be changed without warning the user. If there is an impact to the user, then that impact should be displayed along with the warning. Clusters may make an assumption about disk signatures on shared storage.
Caution: The discovery process must not impact other systems accessing the storage. A long discovery process may "hold" drives and look like a failure of shared storage.