It was discovered in some versions of Oracle VM (3.4.4 and below), that when Rescan Of Physical Disks is invoked via GUI or CLI, it induces FC lip reset causing multipath/scsi disruption which also could lead to ocfs2-level node fence. This can lead to a OVM server to crash or go into read-only mode.
The issue is documented in the following Document from Oracle: Rescan Of Physical Disks Causes Multipath Issues (Doc ID 2321067.1) and can be confirmed from OVM logs and sosreport. Instructions for collecting OVM logs can be found here: Oracle VM: OVM3 Log File Locations (Doc ID 1397877.1)
Addressed through the following Oracle BUG's:
BUG 19144767 - https://linux.oracle.com/errata/OVMBA-2018-0147.html - ENHANCEMENT REQUEST FOR OPTION TO HAVE STORAGE REFRESH ISSUE SCAN VS LIP.
BUG 25931833 - OVM enhanced rescan physical disks to avoid outages.
Solution
The real fix/solution for this issue has been implemented into OVM 3.4.5, the LIP will be option based on the Storage plug in used, by the OVM default or generic plugin this will send the LIP with a "false" flag on it so this will not be used unless you decide to.
Issue discovered on https://jira.purestorage.com/browse/ES-41950 see jira & attached case for full details.