| Measurement |
Description |
Measurement Unit |
Interpretation |
| healthState |
Indicates how healthy this disk currently is. |
|
The values that this measure can report and their corresponding numeric values are discussed in the table below:
| Numeric Value |
Measure Value |
| 0 |
OK |
| 1 |
Unknown |
| 2 |
Degraded/Warning |
| 3 |
Minor failure |
| 4 |
Major failure |
| 5 |
Critical failure |
| 6 |
Non-recoverable error |
Note:
By default, this measure reports the Measure Values discussed above to indicate the state of a disk. In the graph of this measure however, states are represented using the numeric equivalents only. |
| operationalStatus |
Indicates the current operational state of this disk. |
|
The values that this measure can report and their corresponding numeric values are discussed in the table below:
| Numeric Value |
Measure Value |
| 0 |
OK |
| 1 |
In Service |
| 2 |
Power Mode |
| 3 |
Completed |
| 4 |
Starting |
| 5 |
Dormat |
| 6 |
Other |
| 7 |
Unknown |
| 8 |
Stopping |
| 9 |
Stressed |
| 10 |
Stopped |
| 11 |
Supporting Entity in Error |
| 12 |
Degraded or Predicted Failure |
| 13 |
Predictive Failure |
| 14 |
Lost Communication |
| 15 |
No Contact |
| 16 |
Aborted |
| 17 |
Error |
| 18 |
Non-Recoverable Error |
Note:
By default, this measure reports the Measure Values discussed above to indicate the operational state of a disk. In the graph of this measure however, operational states are represented using the numeric equivalents only. |
| detailedStatus |
Describes the current operational state of this disk. |
|
This measure will be reported only if the API provides a detailed operational state.
Typically, the detailed state will describe why the disk is in a particular operational state. For instance, if the operationalStatus measure reports the value Stopping for a disk, then this measure will explain why that disk is being stopped.
The values that this measure can report and their corresponding numeric values are discussed in the table below:
| Numeric Value |
Measure Value |
| 0 |
Online |
| 1 |
Success |
| 2 |
Power Saving Mode |
| 3 |
Write Protected |
| 4 |
Write Disabled |
| 5 |
Not Ready |
| 6 |
Removed |
| 7 |
Rebooting |
| 8 |
Offline |
| 9 |
Failure |
Note:
By default, this measure reports the Measure Values discussed above to indicate the detailed operational state of a disk. In the graph of this measure however, detailed operational states are represented using the numeric equivalents only. |
| dataTransmitted |
Indicates the rate at which data was transmitted by this disk. |
MB/Sec |
|
| iops |
Indicates the rate at which I/O operations were performed on this disk. |
IOPS |
Compare the value of this measure across disks to know which disk handled the maximum number of I/O requests and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in load-balancing across disks.
You may then want to take a look at the reads and writes measure to understand what to fine-tune the load-balancing algorithm for read requests or that of the write requests. |
| reads |
Indicates the rate at which read operations were performed on this disk. |
Reads/Sec |
Compare the value of this measure across disks to know which disk handled the maximum number of read requests and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in load-balancing across disks. |
| writes |
Indicates the rate at which write operations were performed on this disk. |
Writes/Sec |
Compare the value of this measure across disks to know which disk handled the maximum number of write requests and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in load-balancing across disks. |
| dataReads |
Indicates the rate at which data is read from this disk. |
MB/Sec |
Compare the value of these measures across disks to identify the slowest disk in terms of servicing read and write requests (respectively). |
| dataWritten |
Indicates the rate at which data is written to this disk. |
MB/Sec |
| busy |
Indicates the percentage of time this disk was busy processing requests. |
Percent |
Compare the value of this measure across disks to know which disk was the busiest and which disk was not. If the gap between the two is very high, then it indicates serious irregularities in load-balancing across disks. |
| avgReadSize |
Indicates the amount of data read from this disk per I/O operation. |
MB/Op |
Compare the value of these measures across disks to identify the slowest disk in terms of servicing read and write requests (respectively). |
| avgWriteSize |
Indicates the amount of data written to this disk per I/O operation. |
MB/Op |
| readHits |
Indicates the percentage of read requests that were serviced by the cache of this disk. |
Percent |
A high value is desired for this measure. A very low value is a cause for concern, as it indicates that cache usage is very poor; this in turn implies that direct disk accesses, which are expensive operations, are high. |
| writeHits |
Indicates the percentage of write requests that were serviced by the cache of this disk. |
Percent |
| averageResponseTime |
Indicates the time taken by this disk to respond to I/O requests. |
Microsecs |
Ideally, this value should be low. If not, it implies that the disk is slow. |
| queueDepth |
Indicates the number of requests that are in queue for this disk. |
Number |
A consistent increase in this value indicates a potential processing bottleneck with the disk. |