Consumer hard drives typically make many attempts to read a bad sector, causing hangs in RAID arrays. A quick way to solve the issue without having to buy more expensive "RAID-compatible" drives is to enable error recovery control, setting a time limit on the retries. Some drives support this; others do not. What follows is a simple one-liner that, when added to the system crontab, sets error recovery control to 7 seconds in all the drives in the array that support ERC.
AT&T doesn’t provide much support for people using their own equipment, leaving it up to us to figure out configuration issues.
They now support IPv6. The following instructions for an ASUS router (most use the same software) are derived from the information at: IPv6 compatibility for IFITL page hosted by AT&T. My setup uses DSL, not IFITL, and is across the country from the area referred to in AT&T, so I suspect this works throughout the AT&T network.