I visited with a HP storage engineer at a conference and he told me that the I/O module on a 1510i does NOT have the disk configuration information in it’s memory, but that the disk configuration is written on each disk drive. Therefore, if the I/O module fails, you can replace it with another module and the drive configuration (RAID, LUN’s, etc) will not be effected. He also suggested that if the I/O module fails, then you should move the cache memory from the old to the new I/O controller prior to bringing up the system so that the cache will be flushed to the disks.  I definitely recommend contacting HP support if your I/O controller goes out to verify this, but it made me feel better about the recoverability of our SAN.  If you have a spare I/O module on hand, recovering from an I/O module failure should be easy (in theory).