Logical Device Details Test

This test monitors the I/O activity on each logical volume (LDEV) on the storage device, and indicates irregularities in load balancing across the volumes.

Target of the test : A Hitachi USP storage device

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every logical volume on the Hitachi USP device monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.


The IP address of the host for which this test is to be configured.


The port at which the specified host is listening. By default, this is set to NULL.

UserID, Password and Confirm password

The test should be configured with the credentials of a special user account, which is specifically created for use with the export utility; this account should fulfill the following conditions:

  • Should not possess the ‘write’ permission;
  • Can be of any user type; however, to ensure that the eG agent collects statistics pertaining to all storage partitions, it is recommended that this user is of type storage administrator;

Provide the credentials of this user against the UserID and Password parameters. Confirm the password by retyping it in the Confirm Password text box.


Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 3 seconds.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

I/O operations rate

Indicates the number of read-write operations performed on this logical volume per second.


A high value for this measure is indicative of high I/O activity on the logical volume. Comparing the value of this measure across logical volumes can accurately reveal which volumes are extremely busy, and also enable administrators to easily detect irregularities in load distribution across the volumes. 

To uniformly balance load across volumes, you should consider installing additional hardware (e.g., HDDs, disk adapters, cache), or you can use volume migration to migrate high-usage volumes to higher HDD classes and/or to lower-usage parity groups.

Transaction rate

Indicates the rate at which data transfers occur on this logical volume.




Indicates the rate at which data reads are performed on this logical volume.



Write IOPS

Indicates the rate at which data is written to this logical  volume.



Read hits

Indicates the percentage of read requests that were served by this logical volume.


Ideally, the value of this measure should be high. A low value is a cause for concern, as it indicates that a majority of read requests have failed.

Write hits

Indicates the percentage of data written to this logical volume.



Cache-to-disk transfers

Indicates the number of data transfer operations performed from the cache to this logical volume.


A high value for this measure is a sign of good health. A low value or a consistently decreasing value could be a cause for concern, as it indicates that the cache is not writing enough data to the disk; this in turn could overload the cache and hamper its ability to make space for data that is waiting to be written.

Response time

Indicates the current responsiveness of this logical volume to requests.



Ideally, the value of this measure should be low.

Transfers between disk and cache

Indicates the rate at which data is transferred by this logical volume to the cache.