Disk Activity - IGEL Test

This test reports statistics pertaining to the input/output utilization of each physical disk on each IGEL Endpoint.

Target of the test : An IGEL Endpoint

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every combination of IGEL Endpoint:disk_partition

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The nick name of the IGEL Endpoints component for which this test is to be configured.

Port

Refers to the port at which the specified host listens to. By default, this is NULL.

Inside View Using

To obtain the 'inside view' of performance of the IGEL Endpoints - i.e., to measure the internal performance of the IGEL Endpoints - this test uses a light-weight Endpoint Agent software deployed on each of the IGEL Endpoints. The Endpoint Agents collect performance metrics from the IGEL Endpoints and communicate the metrics to the eG remote agent using TCP protocol. Accordingly, by default, this parameter is set to TCP.

Report By User

Since this test runs for an 'IGEL Endpoints' component, this flag is set to Yes by default.

Report Powered OS

Since this test runs for an 'IGEL Endpoints' component, this flag is set to Yes by default.

Is Cloud VMs

Since this test runs for an 'IGEL Endpoints' component, this flag is set to Yes by default.

Disk Busy in Percent

Specify the percentage of time beyond which the test should reveal the detailed diagnosis for the Percent virtual disk busy measure. By default, this parameter is set to 25. However, you can override this value as per your requirement.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. For instance, if you set to 1:1, it means that detailed measures will be generated every time this test runs, and also every time the test detects a problem.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Disk busy

Indicates the percentage of elapsed time during which the disk is busy processing requests (i.e., reads or writes).

Percent

Comparing the percentage of time that the different disks are busy, an administrator can determine whether load is properly balanced across the different disks.

The detailed diagnosis of this measure provides information such as the Process IDs executing on the disk, the Process names, the rate at which I/O read and write requests were issued by each of the processes , and the rate at which data was read from and written into the disk by each of the processes. In the event of excessive disk activity, the details provided in the detailed diagnosis page will enable users to figure out which process is performing the I/O operation that is keeping the disk busy.

Disk busy due to reads

Indicates the percentage of elapsed time that the selected disk drive is busy servicing read requests.

Percent

 

Disk busy due to writes

Indicates the percentage of elapsed time that the selected disk drive is busy servicing write requests.

Percent

 

Disk read time

Indicates the average time in seconds of a read of data from the disk.

Secs

 

Disk write time

Indicates the average time in seconds of a write of data from the disk.

Secs

 

Avg queue length

Indicates the average number of both read and write requests that were queued for the selected disk during the sample interval.

Number

 

Current disk queue length

The number of requests outstanding on the disk at the time the performance data is collected.

Number

This measure includes requests in service at the time of the snapshot. This is an instantaneous length, not an average over the time interval. Multi-spindle disk devices can have multiple requests active at one time, but other concurrent requests are awaiting service. This counter might reflect a transitory high or low queue length, but if there is a sustained load on the disk drive, it is likely that this will be consistently high. Requests experience delays proportional to the length of this queue minus the number of spindles on the disks. This difference should average less than two for good performance.

Disk read rate

Indicates the number of reads happening on a logical disk per second.

Reads/Sec

A dramatic increase in this value may be indicative of an I/O bottleneck on the IGEL Endpoint.

Data read rate from disk

Indicates the rate at which bytes are transferred from the disk during read operations.

KB/Sec

A very high value indicates an I/O bottleneck on the IGEL Endpoint.

Disk write rate

Indicates the number of writes happening on a local disk per second.

Writes/Sec

A dramatic increase in this value may be indicative of an I/O bottleneck on the IGEL Endpoint.

Data write rate to disk

Indicates the rate at which bytes are transferred from the disk during write operations.

KB/Sec

A very high value indicates an I/O bottleneck on the IGEL Endpoint.

Disk service time

Indicates the average time that this disk took to service each transfer request ( i.e., the average I/O operation time)

Seconds

A sudden rise in the value of this measure can be attributed to a large amount of information being input or output. A consistent increase however, could indicate an I/O processing bottleneck.

Disk queue time

Indicates the average time that transfer requests waited idly on queue for this disk.

Seconds

Ideally, the value of this measure should be low.

Disk IO time

Indicates the average time taken for read and write operations of this disk.

Seconds

The value of this measure is the sum of the values of the Disk service time and Disk queue time measures.

A consistent increase in the value of this measure could indicate a latency in I/O processing.

Avg IO read size

Indicates the average number of bytes transferred from disk during read operations.

KB

Larger I/Os tend to have higher latency (for example, BACKUP/RESTORE operations issue 1 MB transfers by default).

Avg I/O write size

Indicates the average number of bytes transferred into disk during write operations.

KB

Split IO

Reports the rate at which the operating system divides I/O requests to the disk into multiple requests.

Splits/Sec

A split I/O request might occur if the program requests data in a size that is too large to fit into a single request or if the disk is fragmented. Factors that influence the size of an I/O request can include application design, the file system, or drivers. A high rate of split I/O might not, in itself, represent a problem. However, on single-disk systems, a high rate for this counter tends to indicate disk fragmentation.