Disk To Cache Load Test

Whenever the storage device experiences heavy workloads, the additional load on the device is transferred to the disk via multiple backend loops. Periodic monitoring of the I/O activity on the loops is essential to identify loops that are heavily loaded, and loops where data is moving slowly or is choking. This test auto-discovers the backend loops that are operational on a storage device, and reports load statistics pertaining to each loop.

Target of the test : A Hitachi AMS storage device

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each backend loop.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.


The IP address of the storage device.


Specify the name of the storage unit to be monitored. To determine the unit name registered with the Storage Navigator Client for the AMS SAN device, run the following commands, one after another, from the C:\Program Files\Storage Navigator Modular CLI directory on the Storage Navigator Client:



The output of the command includes the Name of the storage unit. DF700M_75011118 is a sample unit name.


Indicate the machine type. The value can be AMS or WMS. By default, this parameter is set to AMS.


Specify the full path to the install directory of the storage navigator.


Indicate the duration (in minutes) for which this test should wait for a response from the storage device. By default, this is set to 5 minutes.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

IO rate

Indicates the number of read/write commands transferred to the disk per second via this loop.


If this measure reports a high value or if the value of the measure increases consistently, it is indicative of unusually high I/O activity on this backend loop.  Comparing the value of this measure across loops can accurately indicate which path is currently experiencing heavy traffic. Observing the variations in this measure over a period of time will enable you to identify roadblocks (if any).

Read rate

Indicates the number of read operations performed on the disk via this backend loop per second.



Write rate

Indicates the number of write commands issued on the disk per second via this loop.



Data transfer rate

Indicates the transfer size of read/write commands per second.



Read transfer rate

Indicates the transfer size of read commands per second.



Write transfer rate

Indicates the transfer size of write commands per second.



Online verify command count

Indicates the number of online verify commands executed per second.