HP XP P9000 Performance Advisor Software v5.5 User Guide (T1789-96337, Februrary 2013)

Figure 37 Total I/O Rate
The total backend transfers may be compared to the total frontend I/Os and the difference is due
to the effects of the array cache. The total backend transfers load is taken by the RAID groups and
ACP/DKA pairs, where as the total frontend I/O load is taken by the CHIP/CHA ports.
NOTE: If there are no data points available for the dates selected, a blank chart is displayed. If
all the data values are zero for the dates selected, a chart with a horizontal line along X axis is
displayed in the center of the chart.
Total I/O Rate by hour of day report
The Total I/O Rate by hour of day report displays in a chart format, the number of total read and
write I/O operations per second over the over 24-hour period. “Total I/O Rate by hour of
day” (page 362) displays a sample Total I/O Rate by hour of day report for a P9500 Disk Array.
Report types 361