HP XP P9500 Storage - Manual (Page 82)

Monitoring modes
When you create or edit a pool, you must specify the type of Smart Tiers monitoring mode to be
used: Period mode or Continuous mode. If you change the monitoring mode from one to the other
during monitoring, the new setting becomes effective when the next monitoring starts.
Period mode
Period mode is the default setting. If Period mode is enabled, tier range values and page relocations
are determined based solely on the monitoring data from the last complete cycle. Relocation is
performed according to any changes in I/O loads.
Continuous mode
If Continuous mode is enabled, by weighting the latest monitoring information with the prior
collected monitoring information of past cycles, the weighted average efficiency is calculated. The
tier range value, tier properties performance graph, and tier relocation decisions are based on
the weighted average efficiency. If a temporary decrease or increase of the I/O load occurs,
unnecessary relocation can be avoided by using Continuous mode.
The following illustration compares tier relocation using period mode versus continuous mode:
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
82 Configuring thin provisioning