HP XP7 Storage - Manual (Page 84)

performing the tier relocation based on the weighted average efficiency, even if a temporary
decrease or an increase of the I/O load occurs, unnecessary relocation can be avoided.
Cautions when using monitoring modes
•
If Continuous mode is used, best practice is to collect monitoring information using the following
execution modes:
◦ Auto execution mode
◦ Manual execution mode with collecting the periodic monitoring information by defining
a script using RAID Manager
If the Manual execution mode is used without scripts, the Continuous monitoring mode can
be set. However, in this case, unexpected results may be calculated because the weighted
average efficiency is calculated based on very different duration (short and long) periods
information obtained in the past cycles.
•
When the monitoring mode is set to Continuous, the frequency distributions are displayed for
each pool and V-VOL calculated by using the monitor value on which the weighted calculation
is done.
These calculated values are the predictive values for the next cycle after successfully relocating
all pages. Therefore, these values may differ from an actual monitoring result when they
appear.
In Performance Utilization of each tier, regardless of the type of the monitoring mode setting,
the monitor values which were already collected in the current cycle are displayed.
If you switch the monitoring mode from Period to Continuous or from Continuous to Period,
the current cycle’s monitoring data that is being collected is not discarded. However, the data
calculated by using past monitor cycle information on which the weighted calculation is done
will be reset.
84 Configuring thin provisioning