| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Availability |
Indicates whether/not this datastore is available. |
Percent |
While the value 0 indicates that the datastore is not available, the value 100 indicates that the datastore is currently available. If a datastore becomes unavailable, then VMs that are currently using that datastore could be rendered inaccessible to users. |
| Uncommitted_Space |
Indicates the additional storage space potentially used by this virtual machine on this datastore. |
MB |
Additional space may be needed for example when lazily allocated disks grow, or storage for swap is allocated when powering on the virtual machine.
If the virtual machine is running off delta disks (for example because a snapshot was taken), then only the potential growth of the currently used delta-disks is considered.
|
| Space_used |
The storage space on this datastore that is actually being used by this virtual machine. |
MB |
Comparing the value of this measure across VMs will enable you to quickly identify the VM that is consuming maximum datastore space. |
| Pct_Space_used |
The percentage of space on this datastore that is being consumed by this VM. |
Percent |
If a datastore is experiencing a space crunch, then you can compare the value of this measure across VMs to identify which VM is responsible for it. |
| OtherVm_Space |
The total space on this datastore that is being used by files such as configuration, suspend data, NVRAM, screenshots and others. This does not include Virtual Disks, snapshots or swap files. |
MB |
If a datastore is being rapidly drained of space, then, you can compare the value of the OtherVm_Space and Space_used measure for each VM, so as to quickly isolate what type of files associated with which VM are occupying too much space. |
| Pct_OtherVm_Space |
The percentage of space used on this datastore by other files. |
MB |
If a datastore is being rapidly drained of space, then, you can compare the value of the Pct_OtherVm_Space and Pct_Space_used measures across VMs, so as to quickly isolate what type of files associated with which VM are occupying too much space. |
| Unshared_Space |
Storage space, in bytes, occupied by the virtual machine on this datastore that is not shared with any other virtual machine. |
MB |
|
| Provisioned_Space |
The amount of space on this datastore that has been provisioned for this VM. |
MB |
This is typically the sum total of the disk space used by the VM and the uncommitted space for this VM on this datastore. |
| Virtual_disks |
Indicates the number of virtual disks in this datastore. |
Number |
|
| Swap_Space |
Indicates the amount of space in this datastore that is occupied by the swap file of this VM. |
MB |
A swap file is created by the ESX/ESXi host when a virtual machine is powered on. If this file cannot be created, the virtual machine cannot power on. By default, the swap file is created in the same location as the virtual machine's configuration file.
In the event of a space crunch, you may want to compare the values of the Swap file space, Virtual disk file space, and Snapshot file space measures to figure out which file is contributing to the space contention.
|
| Pct_Swap_Space |
Indicates the percentage of space in this datastore that is occupied by the swap file of this VM. |
Percent |
| Snapshot_Space |
Indicates the amount of space in this datastore that is used for storing a snapshot of this VM. |
MB |
A snapshot captures the entire state of the virtual machine at the time you take the snapshot. Snapshots are useful when you need to revert repeatedly to the same state but you do not want to create multiple virtual machines.
A snapshot includes the following information:
- Contents of the virtual machine's memory
- Virtual machine settings
- State of all the virtual machine's virtual disks
In the event of a space crunch, you may want to compare the values of the Swap file space, Virtual disk file space, and Snapshot file space measures to figure out which file is contributing to the space contention.
|
| Pct_Snapshot_Space |
Indicates the percentage of space that is used for creating a snapshot of this VM in this datastore. |
Percent |
| Virtualdisk_Space |
Indicates the amount of space in this datastore that is occupied by the virtual disk file of this VM. |
MB |
A virtual machine uses a virtual hard disk to store its operating system, program files, and other data associated with its activities. A virtual disk is a large physical file, or a set of files, that can be copied, moved, archived, and backed up as easily as any other file. To store virtual disk files and manipulate the files, a host requires dedicated storage space.
In the event of a space crunch, you may want to compare the values of the Swap file space, Virtual disk file space, and Snapshot file space measures to figure out which file occupies the maximum space in a datastore.
|
| Pct_Virtualdisk_Space |
Indicates the percentage of space available for the virtual disk of this VM in this datastore. |
Percent |
|
| Thin_Provisioned |
Indicates whether this datastore is thin provisioned or not. |
Number |
This measure reports either Yes or No while indicating whether this datastore is thin provisioned or not.
The numeric values that correspond to those states are as follows:
| State |
Numeric Value |
| Yes |
0 |
| No |
1 |
Note:By default, this measure reports the above-mentioned states while indicating whether this datastore is thin provisioned or not. However, the graph of this measure will be represented using the corresponding numeric equivalents of the states as mentioned in the table above. |
| Pct_Saved_Space |
Indicates the percentage of space saved by this VM in this datastore. |
Percent |
|
| Write_Request |
Indicates the average number of write commands issued per second to this datastore by this VM during the collection interval. |
Commands/Sec |
|
| Read_Request |
Indicates the average number of read commands issued per second to this datastore by this VM during the collection interval. |
Commands/Sec |
|
| Write_Latency |
Indicates the average amount of time taken for a write by this VM from the perspective of this datastore. |
Secs |
A high value indicates that the VM is taking too long to write to the datastore. Compare the value of this metric across VMs and datastores to know which VM registered the maximum write latency with respect to which datastore. |
| Read_Latency |
Indicates the average amount of time taken for a read by this VM from the perspective of this datastore. |
Secs |
A high value indicates that the VM is taking too long to read from the datastore.
Compare the value of this metric across VMs and datastores to know which VM registered the maximum read latency with respect to which datastore. |
| Read_Rate |
Indicates the rate at which data is read from this datastore. |
MB/Sec |
A high value is desired for these measures. A low value or a consistent dip in the value is indicative of an I/O latency. |
| Write_Rate |
Indicates the rate at which data is written to this datastore. |
MB/Sec |
| Total_latency |
Indicates the total amount of time taken to read from and write into this datastore from the perspective of guest operating system. |
Secs |
A high value or a consistent rise in the value of this measure is a cause for concern, as it indicates a current/potential I/O processing bottleneck with the datastore. |
| Throughput |
Indicates the rate at which the data is read from or written into this datastore. |
MB/Sec |
Ideally, the value of this measure should be high. A sudden or steady drop in this value could indicate a gradual deterioration in the performance of the datastore, probably owing to a processing bottleneck. |
| Total_iops |
Indicates the total number of read and write commands issued per second to this datastore. |
Commands/Sec |
Compare the value of this measure across datastores to identify the busiest datastore in terms of the rate at which read/write commands are issued on it. A consistent increase in the value of this measure for a particular datastore could indicate a potential I/O overload. |