Performance of One RAID Array report

Shows four charts, and a table of performance metrics for a RAID array over a time period. Use the report to analyze the performance of a RAID array.

Restriction: This report applies only to DS8000® systems.

Charts

The charts show the following performance statistics for arrays on storage systems:

The total I/O rates, and the total response times
The read I/O rates, the write I/O rates, the read response times, and the write response times
The back-end I/O rates, and the back-end I/O response times
The back-end read I/O rates, the back-end write I/O rates, the read response times, and the write response times

Report output

The following information is provided in the report for the period that you specified:

Storage System Name: A user-defined name of the storage system. If a name was not defined, IBM Spectrum® Control shows the name that was defined when the storage system was added for monitoring.
Storage System Controller Name: The name that was assigned to the controller when it was added to the system.
Storage RAID Array Name: The name that was assigned to the RAID array when it was added to the system.
Overall Read I/O Rate (ops/s): The average number of read operations per second. This value includes both sequential and nonsequential read operations.
Overall Write I/O Rate (ops/s): The average number of write operations per second. This value includes both sequential and nonsequential write operations.
Total Overall I/O Rate (ops/s): The average number of read operations and write operations per second. This value includes both sequential and nonsequential operations.
Read Response Time (ms/op): The average number of milliseconds to complete a read operation.
Write Response Time (ms/op): The average number of milliseconds to complete a write operation.
Overall Response Time (ms/op): The average number of milliseconds to complete an I/O operation. This value includes both read and write operations.
Back-End Read I/O Rate (ops/s): The average number of read operations per second that are issued to the back-end storage resources.
Back-End Write I/O Rate (ops/s): The average number of write operations per second that are issued to the back-end storage resources.
Total Back-End I/O Rate (ops/s): The average number of I/O operations per second that are transmitted between the back-end storage resources and the component. This value includes both read and write operations.
Back-End Read Response Time (ms/op): The average number of milliseconds for the back-end storage resources to respond to a read operation.
Back-End Write Response Time (ms/op): The average number of milliseconds for the back-end storage resources to respond to a write operation.
Overall Back-End Response Time (ms/op): The average number of milliseconds for the back-end storage resources to respond to a read or a write operation.
Disk Utilization Percentage: The average percentage of time that the disks that are associated with an array are busy.; No value is calculated for this property if there are multiple ranks in the extent pool where the thin-provisioned volumes are allocated. In this case, the value N/A is displayed. This limitation applies only to DS8000 storage systems.; If there is only a single rank in the extent pool, the value for this property is calculated regardless of the thin-provisioned volumes.; Tip: Some highly sequential workloads such as batch or backup processing might continually exceed the threshold because they drive the arrays to high utilization percentages. For these types of workloads, a high utilization indicates that the work is being performed very efficiently and is not a cause for concern.; For DS8000 storage systems, this property is available only for 8.5.0 and later. For earlier versions, the value N/A is shown.

Related reports

To open the Most Active RAID Arrays report, click the name of the storage system in the report table.