Incorrect or missing monitoring data

Incorrect monitoring data

Incorrect monitoring data (for example, a negative value) might be displayed when the LDEV is formatted. Also, the value of monitoring data immediately after the storage system is power cycled could be extremely large.

Missing monitoring data

When the target monitoring data cannot be collected, no error occurs, and the processing continues.

Causes:

1. When the period of collecting monitoring data that is specified in the export tool is outside the collection period of accumulated monitoring data, the performance value in the period is not output.

   When data that is accumulated in cache flash memory (CFM) is updated while monitoring data is collected, the above phenomenon (performance value is not output) occurs around the start time of the specified period.

2. Monitoring data might not be collected because the storage system is rebooting, because the storage system has a heavy load, or because a temporary network error occurs.
   • When part of the monitoring data cannot be collected, performance metrics are not output for that part.
   • When monitoring data of some plots cannot be collected, performance metrics are not output for the plots.
   • When a CTL or CFM is replaced, the performance information associated with the corresponding CTL is initialized. However, since performance information is accumulated in all CTLs, if the replacement targets only certain CTLs or CFMs, the performance information is retained in the CTLs that were not replaced. If maintenance involves replacing all CTLs or CFMs, the performance information is not preserved. If performance information is required, make sure to collect it before performing the replacement.
   • When replacing a CTL or CFM, the performance information associated with the corresponding CTL will be initialized. However, since performance information is accumulated in all CTLs, if the replacement only targets certain CTLs or CFMs, the performance information will be retained in the CTLs that were not replaced. If maintenance involves replacing all CTLs or CFMs, the performance information will not be preserved. If performance information is required, make sure to collect it before performing the replacement.