On my IBM x3650 M4, running FreeBSD 10.1-RELEASE I'm using the mfi driver with the builtin M5110e RAID controller. Then I thought to try the mrsas driver even the M5110e is not listed in the documentation. I set the
flag at the loader prompt. Then FreeBSD started, the volumes where listed as da* devices but I was not able to mount the root filesystem. Then I started the machine again with mfi enabled. But then I noticed that all volumes are corrupted, which means that even the GPT was gone.
The problem seems to be reproducible: A second try had the same result.
I don't know if it's intended that the M5110 should run with mrsas. If not, it should not damage the volumes. At least there should be a clear warning in the man page.
The machine is not in production use at the moment, so I can do more testing if required.