I have a "search" problem after upgrading my iMac Pro to OS X Mojave 10.14. Spotlight search for files ending with .jpg on the Pegasus3 R4 RAID displays a spinner and no results - I have allowed this to continue for over an hour. Same search to same RAID in OS X High Sierra 10.13 displays image files quickly.
Apple support asked if the RAID was compatible with Mojave so I have an inquiry open to Promise Support.