This statistic shows iSCSI operations/sec (iSCSI IOPS) requested by initiators to the appliance. Various useful breakdowns are available: to show the initiator, target, type and latency of the iSCSI I/O.
iSCSI operations/sec can be used as an indication of iSCSI load, and can also be viewed on the dashboard.
Use the latency breakdown when investigating iSCSI performance issues, especially to quantify the magnitude of the issue. This measures the I/O latency component for which the appliance is responsible for, and displays it as a heat map so that the overall latency pattern can be seen, along with outliers. If the iSCSI latency is high, drill down further on latency to identify the client initiator, the type of operation and LUN for the high latency, and, check other statistics for both CPU and Disk load to investigate why the appliance is slow to respond; if latency is low, the appliance is performing quickly, and any performance issues experienced on the client initiator are more likely to be caused by other factors in the environment: such as the network infrastructure, and CPU load on the client itself.
The best way to improve performance is to eliminate unnecessary work, which may be identified through the client initiator, lun and command breakdowns.
These breakdowns can be combined to produce powerful statistics. For example:
"Protocol: iSCSI operations per second of command read broken down by latency" (to examine latency for SCSI reads only)
See Protocol: iSCSI bytes for the throughput of this iSCSI I/O; also see Cache: ARC accesses broken down by hit/miss to see how well an iSCSI read workload is returning from cache, and Disk: I/O operations for the back-end disk I/O caused.