Disk Activity - Console Test

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

Target of the test : An ESX server 3/3.5/4.0

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the ESX server being monitored

Configurable parameters for the test
  1. Test period - How often should the test be executed
  2. Host - The host for which the test is to be configured.
  3. console user - Provide the name of a valid user to the ESX server being monitored.
  4. console password - Specify the password of the console user here.
  5. confirm password - Confirm the console password by retyping it here.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Percent 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.

Disk read time:

Indicates the average time (in seconds) taken by the disk to read data.

Secs

Ideally, the value of this measure should be low.

Disk write time:

Indicates the average time (in seconds) taken by the disk to write data.

Secs

Ideally, the value of this measure should be low.

Reads from disk :

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 guest.

Data reads from disk:

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

Kbytes/Sec

A very high value indicates an I/O bottleneck.

Writes to disk:

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

Writes/Sec

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

Data writes to disk:

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

Kbytes/Sec

A very high value indicates an I/O bottleneck.

Avg queue for disk:

Indicates the average number of both read and write requests that were queued for this disk during the last measurement period.

Number

A consistent and significant increase in the value of this measure for a particular disk could indicate an I/O overload that could be choking the disk, rendering it unable to process I/O requests quickly.

Current queue for disk:

Indicates the number of requests currently outstanding on the disk.

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 measure 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.

Percent reads from disk:

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

Percent

 

Percent writes to disk:

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

Percent