Please try to check your system RAM (memory) health by running the Memtest tool ( reboot your system, and it will appear as first option to check the memory ).
Also you may try to check your file system by using the file system repair tool ( please check your RAID controller health and storage disks health first before running the tool): http://kb.open-e.com/File-system-repair_138.html
And you may update the controller firmware for more stability.