# Detailed performance statistics for Amazon EC2 instance store volumes
Amazon EC2 provides real-time, high-resolution performance statistics for NVMe instance store volumes attached to Nitro-based Amazon EC2 instances. These statistics are presented as aggregated counters that are retained for the duration of the instance's lifetime. The statistics provide details about the cumulative number of operations, bytes sent and received, time spent on read and write I/O operations, and histograms for read and write I/O operations. While these statistics maintain consistency with [Amazon EBS detailed performance statistics](https://docs.aws.amazon.com/ebs/latest/userguide/nvme-detailed-performance-stats.html), they also include detailed latency histograms broken down by I/O size, which can provide more granular insights into your storage performance patterns. This enhanced visibility enables you to precisely identify which specific I/O sizes are experiencing latency issues, allowing you to optimize application performance and troubleshoot issues more effectively.
You can collect these statistics at a granularity of up to 1 second intervals. If requests are made more frequently than 1 second intervals, the NVMe driver might queue the requests, along with other admin commands, to be processed at a later time.
**Considerations**
+ The statistics are supported only for NVMe instance store volumes attached to Nitro-based instances.
+ The counters are not persistent across instance stops and restarts.
+ The statistics are available at no additional cost.
## Statistics
The NVMe block device vends the following statistics:
| Statistic name | Full name | Type | Description |
| --- | --- | --- | --- |
| total\$1read\$1ops | Total read operations | Counter | The total number of completed read operations. |
| total\$1write\$1ops | Total write operations | Counter | The total number of completed write operations. |
| total\$1read\$1bytes | Total read bytes | Counter | The total number of read bytes transferred. |
| total\$1write\$1bytes | Total write bytes | Counter | The total number of write bytes transferred. |
| total\$1read\$1time | Total read time | Counter | The total time spent, in microseconds, by all completed read operations. |
| total\$1write\$1time | Total write time | Counter | The total time spent, in microseconds, by all completed write operations. |
| instance\$1store\$1volume\$1performance\$1exceeded\$1iops | Total time demand exceeded volume's maximum IOPS | Counter | The total time, in microseconds, that IOPS requests exceeded the volume's maximum IOPS. Any value above 0 indicates that your workload demanded more IOPS than the volume could deliver. Ideally, the incremental count of this metric, between two snapshot times, should be minimal. |
| instance\$1store\$1volume\$1performance\$1exceeded\$1tp | Total time demand exceeded volume's maximum throughput | Counter | The total time, in microseconds, that throughput requests exceeded the volume's maximum throughput. Any value above 0 indicates that your workload demanded more throughput than the volume could deliver. Ideally, the incremental count of this metric, between two snapshot times, should be minimal. |
| volume\$1queue\$1length | Volume queue length | Point in time | The number of read and write operations waiting to be completed. |
| read\$1io\$1latency\$1histogram | Read I/O histogram | Histogram \$1 | The number of read operations completed within each latency bin, in microseconds. |
| write\$1io\$1latency\$1histogram | Write I/O histogram | Histogram \$1 | The number of write operations completed within each latency bin, in microseconds. |
**Note**
\$1 Histogram statistics represent only I/O operations that have completed successfully. Stalled or impaired I/O operations are not included, but will be evident in the `volume_queue_length` statistics, which is presented as a point-in-time statistic.
## Accessing the statistics
The statistics must be accessed directly from the instance to which the instance store volumes is attached. You can access the statistics using one of the following methods.
### Linux instances
------
#### [ Amazon CloudWatch ]
You can configure the Amazon CloudWatch agent to collect the statistics from your instance and make them available as custom metrics in CloudWatch. You can then use the metrics in CloudWatch to analyze I/O patterns, track performance trends, create custom dashboards, and set up automated alarms based on performance thresholds.
For more information about configuring the CloudWatch agent, see [ Collect Amazon EC2 instance store volume metrics](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/Container-Insights-metrics-instance-store-Collect.html).
------
#### [ nvme-cli tool ]
**To access the statistics**
1. Connect to the instance to which the volume is attached.
1. Amazon Linux 2023 AMIs released after September 15, 2025 include the latest version of the `nvme-cli` tool. If you are using an older Amazon Linux AMI, update the `nvme-cli` tool.
```
sudo yum install nvme-cli
```
1. Run the following command and specify the device name for the volume.
```
sudo nvme amzn stats /dev/nvme0n1
```
The statistics also provide detailed latency histograms broken down by I/O size. To view statistics broken down by I/O size, include the `--details` option. For example:
```
sudo nvme amzn stats --details /dev/nvme0n1
```
You can get more information about how to use the tool by specifying the `--help` option. For example:
```
sudo nvme amzn stats --help
```
------
### Windows instances
------
#### [ nvme\$1amzn.exe tool ]
**To access the statistics**
1. Connect to the instance to which the volume is attached.
1. Make sure that you're using AWSNVMe driver version `1.7.0` or later. For more information about updating the AWSNVMe driver, see [AWS NVMe drivers](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/aws-nvme-drivers.html).
1. Get the disk number for the volume. For more information, see [Map NVMe disks on Amazon EC2 Windows instance to volumes](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/windows-list-disks-nvme.html).
1. Run the following command as Administrator and specify the disk number for the volume.
```
.\nvme_amzn.exe stats disk_number
```
The statistics also provide detailed latency histograms broken down by I/O size. To view statistics broken down by I/O size, include the `--details` option. For example:
```
.\nvme_amzn.exe stats --details disk_number
```
------