| When we compared the information in the two tables, we observed that RAID5 had a 30 percent, to over 200 percent, relative impact on response time. You can see this in the following graph. When we test response time, we often refer to both the absolute and the relative response time of a Domino server. The absolute response time is the measured time reported by Notesnum.exe. Notesnum is a utility that aggregates the response time from each Notes client simulator (we used up to five) to produce an overall response time average for all the simulated users. The relative response time is the difference in time between the series data point (in this case, the relative difference between the response time at four CPUs using RAID0 and four CPUs using RAID5).
However, as you can see in the following graph, the absolute response times were much better at the higher load values. The small-value response times (for example, 100ms versus 250ms) produced large relative response time differences (so it's important to assess both the absolute and relative values when making decisions). You should interpret this data as indicating that RAID5 did have an impact, but not a substantial impact. The increased data reliability provided by RAID5 is worth the increase in resource utilization. End users would not perceive any response time difference between 100ms and 250ms.
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