HP XP Performance Advisor Software - Manual (Page 61)

D Comparing LDEV response time metrics
in XP Performance Advisor and XPWatch
Maximum values of LDEV response time in XP Performance
Advisor and XPWatch
The maximum values of LDEV response time in XP Performance Advisor cannot be compared with the
response time values in XPWatch because XP Performance Advisor displays the I/O response time
as separate metrics for read and write, respectively.
XP Performance Advisor also displays the maximum and average values for LDEV response time for
reads and writes separately. The maximum values of the read and write response are displayed within
an interval of 30 seconds.
However, XPWatch does not display any related metric for the maximum value of read or write
response.
Average values of LDEV response time in XP Performance
Advisor and XPWatch
You can calculate the Average Read Response time and Average Write Response time using the
following formulae:
Average read response time
Front–end read response time over the collection interval / total front–end reads
Average write response time
Front-end write response time over the collection interval / total front–end writes
Because XPWatch displays the cumulative LDEV response time (that is, both reads and writes combined)
a direct comparison of the average values of LDEV response time in XP Performance Advisor and
XPWatch is not allowed.
XPWatch and XPSketch Reference Guide 61