RAID Scaling Charts, Part 2

RAID 5 I/O Performance

Do you care about I/O performance for file servers, Web servers, databases or workstations? Then forget everything we’ve seen on scaling, as every additional drive will give you a noticeable performance boost at high command queue depths. At queue depths of four and up, each additional hard drive adds at least 50 more I/O operations per second, which is significant for high-performance applications. The fact that RAID 5 arrays, with many hard drives, provide even fewer I/O operations per seconds with no command queue compared to arrays with few drives shows us one thing: A RAID 5 with multiple hard drives is absolutely unsuitable for desktop applications due to the long access times.