HP XP20000 User Manual page 26

display the monitoring data while the storage system is powered off. The monitoring data imme-
diately after powering on again might contain extremely large values.
Viewing the Physical tab
You will be able to view usage statistics that have been obtained for the last three months (that
is, 93 days) in long-range monitoring, and for the last 15 days in short-range monitoring. You
will not be able to view usage statistics that expired after these storing periods because such
statistics are erased from the storage system.
In short range, if I/O workloads between hosts and the storage system become heavy, the
storage system gives higher priority to I/O processing than monitoring processing, therefore,
a part of monitoring data might be missing. In case that monitoring data is missing frequently,
use the Gathering Interval option in the Monitoring Options window to change the collection
interval longer. For details, see
Window" on page 52.
Short-range monitoring data and long-range monitoring data may have some margin of error.
Viewing the LDEV, Port-LUN, and WWN tab
Monitoring results are stored for the last 8 hours to 15 days depending on the specified gath-
ering interval. If the storing period has passed since a monitoring result was obtained, the
result is erased from the storage system and you will not be able to view that monitoring result.
If I/O workloads between hosts and the storage system become heavy, the storage system
gives higher priority to I/O processing than monitoring processing, therefore, a part of monit-
oring data might be missing. In case that monitoring data is missing frequently, use the Gath-
ering Interval option in the Monitoring Options window to change the collection interval longer.
For details, see "Start
The statistics of monitoring data of pool volumes is included in the statistics of monitoring data
of V-VOLs. For this reason, the pool volumes are not displayed in LDEV tab.
Viewing the WWN tab
To start monitoring traffic between host bus adapters and storage system ports, you must make
settings before starting monitoring. For details, see the HP StorageWorks XP24000/XP20000
Performance Control User Guide.
Displaying monitoring data
In lists of the Auto LUN window contents, a hyphen (-) might be displayed in monitoring data
columns. It means that the statistics of that monitoring item cannot be collected.
If the SVP is overloaded, more time than the gathering interval allots might be required for
updating the display of monitoring data. In this case, some portion of monitoring data will not
be displayed in the window. For example, suppose that the gathering interval is 1 minute. In
this case, if the display in the Auto LUN window is updated at 9:00 and the next update occurs
at 9:02, the window (including the graph) does not display the monitoring result for the period
of 9:00 to 9:01. This situation occurs when you use a Remote Web Console computer, as well
as when the SVP is used to perform maintenance operations for the DKC.
After you set Monitoring Switch to Enable, the SVP might be overloaded for up to 15 minutes
if Performance Monitor receives a couple of data items.
After LDEVs are installed or CUs to be monitored are added, the SVP might be overloaded for
up to 15 minutes if Performance Monitor receives a couple of data items.
Replacing the microcode
After the microcode is replaced, the monitoring data is not stored until a service engineer releases
the SVP from Modify mode. Inaccurate monitoring data may be temporarily displayed.
26 About Performance Monitor
"Start Monitoring" on page 57 and
Monitoring" on page 57 and
"Monitoring Options
"Monitoring Options Window" on page 52.