Most higher-end RAID cards have the option to purchase a battery add-on to allow the controller to finish writing the contents of the cache to the drives in the event of a power failure.
I setup RAIDs on the cheap without ever paying for the battery backup. How much risk is there in losing the cached data if my computer has a UPS? I suppose the computer could overheat and shutoff power to the motherboard in spite of the UPS. Would the RAID battery protect the cache during an overheat shutdown?
How long does the data stay in the cache before being written to the drive? Can I safely assume any write operations sent to the controller are out of the cache after a few seconds or less?