RAID problem on Feb 18th

"There was a disk failure in the Einstein@Home project server on February 17 at 20:47:08 UTC which was handled correctly by the RAID controller hardware but not by the OS driver, resulting in an unwritable file system."

Hey guys,
I was just reading the explination that was posted on the front page and was curious about a few things I hope someone can explain. I have been researching RAID5 for a backup system that I am responsible for putting together in the near future and would like to hear a bit more about what happened with the OS driver and if you have any ideas/suggestions on how to prevent such things in the future.

I understand how RAID5 works, I am just interested in how people have dealt with issues so I can have some clue where to start if I face similar issues down the road. If someone has any suggestions/advice to add, I would be appreciative.

Thank you in advance.