HP XP7 Storage - Manual (Page 12)

◦ Replacing the microprogram
◦ Formatting or quick formatting logical devices
◦ Adding, replacing, or removing MP blades
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Storage system power-off
If the storage system is powered off during monitoring, monitoring stops while the storage
system is powered off. When the storage system is powered up again, monitoring continues.
However, Performance Monitor cannot display information about the period while the storage
system is powered off. Therefore, the monitoring data immediately after powering on again
might contain extremely large values.
•
Microprogram replacement
After the microprogram is replaced, monitoring data is not stored until the service engineer
releases the SVP from Modify mode. While the SVP is in Modify mode, inaccurate data is
displayed.
Cautions and restrictions for usage statistics
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Retention of short-range usage statistics
In the short range, monitoring results are retained for the last 1 to 15 days depending on the
specified sampling interval. If the retention period has passed since a monitoring result was
obtained, the previous result has been deleted from the storage system and cannot be
displayed.
•
Retention of long-range usage statistics
Usage statistics for the last six months (186 days) are displayed in long-range monitoring,
and usage statistics for up to the last 15 days are displayed in short-range monitoring. Usage
statistics outside of these ranges are deleted from the storage system.
•
Statistics for periods of high I/O workload
For short-range monitoring, if the host I/O workload is high, the storage system gives higher
priority to I/O processing than to monitoring. If this occurs, some monitoring data might be
missing. If monitoring data is missing frequently, use the Edit Time Range option to lengthen
the sampling interval. For details, see
“Starting monitoring” (page 14) .
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Volumes and CU ranges
The volumes to be monitored by Performance Monitor are specified by control unit (CU). If
the range of used CUs does not match the range of CUs monitored by Performance Monitor,
usage statistics may not be collected for some volumes.
•
Reverse resync operations
When you run the RAID Manager horctakeover or pairresync-swaps command for a Cnt Ac-J
pair or the BCM YKRESYNC REVERSE command for a Cnt Ac-J Z pair, the primary and
secondary volumes are swapped. You can collect the before-swapped information immediately
after you run any of the commands. Incorrect monitoring data will be generated for a short
time but will be corrected automatically when the monitoring data gets updated. The incorrect
data will also be generated when the volume used for a secondary volume is used as a primary
volume after a Cnt Ac-J or Cnt Ac-J Z pair is deleted.
•
Display of monitoring data immediately after monitoring starts or immediately after the sampling
interval is changed
Monitoring data cannot be displayed immediately after monitoring starts or immediately after
the sampling interval is changed, because no monitoring data has accumulated. “Immediately
after” here means the time within the first two sampling intervals after the monitoring starts or
12 Performance Monitor operations