I got this error in a environment with HP DL760 and DotHill Storage connected in a LSI HBA. In the HP DL760 I have another HBA that does not have anything connected. After I disabled the Emulex adapter and a reboot, the event was gone.
As per Microsoft: "This problem occurs if the host bus adapter (HBA) miniport driver does not report storage devices to the server in a timely manner. If the HBA miniport driver does not report storage devices to the server during server startup, the disk devices will be unavailable to the server. Therefore, the storage devices do not automatically come online. If one or more members of a dynamic disk set do not eventually come online, the complete volume may be inaccessible until all members of the set come online. Generally, you can bring the dynamic disks online manually or by using a script that calls the Diskpart.exe utility to bring the disks online. However, you will most likely experience this same problem the next time that you restart the server. To resolve this problem, contact your SAN vendor to make sure that the firmware, the drivers, and the configuration are up-to-date and are configured correctly". See ME828860
for more details.
I got this message on a Windows 2000 server with RAID 1 after I disconnected the mirrored drive for test purposes.
On a RAID-configured volume this message indicates that one drive failed (or is otherwise unavailable) so now the data is protected by the RAID redundancy. Verify the hard drives and replace and rebuild the RAID as necessary as the data is now vulnerable.