You're right I was thinking you had one system when i asked that, that's what I get for skimming forum threads while writing and rebuilding a system...Anything is possible. But the four failed drives are on three different systems, so very little common footprint. One system is on X11SRH-f MB SATA through an SM216A backplane, one is Xeon-D with build in LSI2116 connected on a SAS-2 expander backplane. The system with two failed drives has one drive on the MB SATA and the other on an LSI230808i, all direct connect backplanes. Four failed drives, three systems, four separate controllers. Nothing common at all.