Vendors won't hesitate to tell you how beautifully parity-based RAID (RAID-5, RAID-6, RAID-4, etc.) works in their storage subsystems, making it almost unnecessary to use any type of striped/mirrored RAID protection. Users may see it as a way of getting a lot more usable storage out of the subsystem but, as the old adage warns, "Nothing in life is free." The same principle applies to storage: What you get back in usable storage, you pay for with processing power. One of the most common problems I encounter during storage assessments is a lack of attention to matching the workload profile of the application to how storage is provisioned in the array. This is often driven by sheer economics but, even when it isn't, bad storage practices can simply result in a poorly balanced system that shows signs of stress. Stress is the asymmetrical impact on various components in the array, such as cache, front-end ports, back-end disk directors and the backplane.