Well, with the areca controllers, make absolute sure that you have the LATEST FIRMWARE. That's v1.46, but NOT JUST ANY VERSION 1.46!!! You MUST have the latest version, which has released January 2009. If it's before that, then it you might have a problem with time-out issues (i.e. a drive will fail out of an array under high load because it doesn't return data to the controller in time). This is a problem with some SAS drives (I think the 1TB 7200 RPM seagate ones), and might also be a problem with the ES.2 drives under the arc-1680 raid cards.

Bottom line is make sure your areca raid cards have the latest firmware. There's an older version of 1.46 and a newer version. Make sure you have the NEWER one that was released after January 2009!

If you DO have two drives fail in a RAID 5 under Areca, DON'T PANIC! There are ways to get your RAID functional again, as long as your drives aren't COMPLETELY toast. A lot of times you have a drive fail, the drive will still work, but it just timed out so it was dropped from the array.

Also, make sure you have firmware sn06 or later on your ES.2 drives.