Disk Volumes Test

A volume or logical drive is a single accessible storage area with a single file system, typically (though not necessarily) resident on a single partition of a hard disk. If a single disk volume in VNX is over-utilized or is unable to process I/O requests quickly, it can damage the user experience with the entire storage system. It is hence the responsibility of the storage administrator to keep an eye out for space contentions and processing bottlenecks with each of the disk volumes in VNX, detect such anomalies even before they occur, and resolve them before users complain. The Disk Volumes test helps the storage administrator discharge his duties efficiently.

This test auto-discovers the disk volumes and reports the processing ability and disk usage of each of the volumes. This enables administrators to proactively detect a potential slowdown in processing or a probable disk contention, identify which disk volume is contributing to these abnormal phenomena, and intervene to ensure that the problem is resolved before it spirals out of control.

Target of the test : An EMC VNX Unified Storage system

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each disk volume in the EMC VNX Unified Storage system.

Configurable parameters for the test

Parameter	Description
Test Period	How often should the test be executed.
Host	The IP address of the storage device for which this test is to be configured.
Controller Station IP	The Control Station is the management station for the VNX for File system, and enables control and configuration of the system. The eG agent uses the CLI that runs on the Control Station to monitor and manage the performance of the VNX for File system. To enable the eG agent to use this CLI, specify the IP address of the Control Station in the Controller Station IP text box. By default, the IP address of the host will be displayed here.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Queue depth	Indicates the number of input/output requests that were pending for this disk volume.	Number	Queue Depth is the number of outstanding I/O requests a disk volume will issue or hold before the disk volume can trigger a Queue Full response i.e., the number of I/O operations that can run in parallel on the disk volume. Queue depth is usually set too high and hence could contribute significantly to latency if improperly set.
Read operations	Indicates the rate at which read operations were performed on this disk volume.	Ops/Sec	A consistent decrease in the value of these measures for a disk volume indicates an I/O processing bottleneck.
Write operations	Indicates the rate at which write operations were performed on this disk volume.	Ops/Sec
Data read	Indicates the rate at which data is read from this disk volume.	KiB/Sec	A consistent decrease in the value of these measures for a disk volume indicates an I/O processing bottleneck.
Data written	Indicates the rate at which data is written to this disk volume.	KiB/Sec
Average read data	Indicates the amount of data read from this disk volume per request.	KB/Request	A consistent decrease in the value of these measures for a disk volume indicates an I/O processing bottleneck.
Average write data	Indicates the amount of data written to this disk volume per request.	KB/Request
Percent utilization	Indicates the percentage of disk that is currently utilized in this disk volume.	Percent	A value close to 100 is an indication that the disk volume is about to run out of disk space. You may want to consider more disk drives to the volume, in this case, to make more space.