Cautions and restrictions for monitoring
Performance monitoring switch
When the monitoring switch is set to disabled, monitoring data is not collected.
Changing the SVP time setting
If the SVP time setting is changed while the monitoring switch is enabled, the following monitoring errors can occur:
Invalid monitoring data appears.
No monitoring data is collected.
If you have changed the SVP time setting, disable the monitoring switch, and then re-enable the monitoring switch. After that, obtain the monitoring data. For details about the monitoring switch, see Starting monitoring.
WWN monitoring
You must configure some settings before the traffic between host bus adapters and storage system ports can be monitored. For details, see Adding new WWNs to monitor, Adding WWNs to ports, and Connecting WWNs to ports.
Parity group monitoring
To correctly display the performance statistics of a parity group, all volumes belonging to the parity group must be specified as monitoring targets.
Storage system maintenance
If the storage system is undergoing the following maintenance operations during monitoring, the monitoring data might not be valid:
Adding, replacing, or removing cache memory
Adding, replacing, or removing data drives
Changing the storage system configuration
Replacing the firmware
Formatting or quick formatting logical devices
Adding, replacing, or removing MP units
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.
Firmware replacement
After the firmware is replaced, monitoring data is not stored until the service engineer releases the SVP from Modify mode. Therefore, inaccurate data might be temporarily displayed.