Dell PowerVault ME5 Series Administrator's Guide

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Performance metrics

The following system performance metrics and statistics are displayed on the Performance panel.

Table 1. Available performance metrics
Metric	Description	Storage Object^1,2
Metric	Description	Controller	Host port	Pool	System	Volume
IOPs	Total—Sum of read IOPs and write IOPs. Read—Number of I/Os per second. Write—Number of I/Os per second	✓	✓	CLI	✓	✓
Throughput	Total—Sum of read bytes per second and write bytes per second. Read—Number of bytes read per second. Write—Number of bytes written per second	✓	✓	CLI	✓	✓
Latency	Average Response time—Average response time of an operation in microseconds. Operations include both reads and writes. Max Response time—Sum of read maximum response time and write maximum response time. Total—Sum of read and write average responses in microseconds. Read Average—I/O read average response time in microseconds. Write Average—I/O write average response time in microseconds. Total—Sum of read and write maximum responses in microseconds. Read Max—Maximum I/O read response time in microseconds. Write Max—Maximum I/O write response time in microseconds.	✓	✓	CLI	✓	✓
Average Queue Depth	Read—Average number of pending read operations being serviced since the last sampling time. This value represents periods of activity only and excludes periods of inactivity. Write—Average number of pending write operations being serviced since the last sampling time. This value represents periods of activity only and excludes periods of inactivity.	-	✓	CLI	-	✓
Cache	Read Ahead Ops—Number of times that read ahead pre-fetched data for host reads. Small Destages—Number of partial stripe destages. (These tend to be very inefficient compared to full stripe writes.) Write Cache Percent—Percentage of write cache currently being used in tenths of a percent. Write Cache Space—Current size of write cache in 16KB chunks.	✓	-	CLI	-	✓

¹ Metrics for the Pool storage object are not graphed in the PowerVault Manager, but are accessible via the CLI.

² Metrics for the System storage object are synthesized from data captured by Controller storage objects in the storage system.