Performance in WinBench 99

Finally, here are data-transfer graphs recorded in WinBench 99:

• Data-transfer graph for a single Fujitsu MBA3073RC disk on the LSI controller

And these are the data-transfer graphs of the RAID arrays built on the Promise SuperTrak EX8650 controller:

• RAID0, 4 disks
• RAID0, 8 disks
• RAID10, 4 disks
• RAID10, 8 disks
• RAID10, 8 disks minus 1
• RAID5, 4 disks
• RAID5, 8 disks
• RAID5, 8 disks minus 1
• RAID6, 8 disks
• RAID6, 8 disks minus 1
• RAID6, 8 disks minus 2

The following diagram compares the read speeds of the arrays at the beginning and end of the partitions created on them:

Yes, the RAID6 gets very weak when it loses two disks. Take note of the performance of the eight-disk arrays: all of them, save for the RAID10, have identical speeds at the beginning and end, and their graphs are flat lines. And their speed is rather low. It looks like the controller indeed has a limit of maximum linear speed due to the peculiarities of its architecture. There is a bottleneck whose bandwidth is not sufficient for reading simultaneously from eight disks each of which can yield over 100MBps.