---
name: "nvme-top"
section: "1"
platform: "linux"
package: "nvme-cli"
version: "3.2-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/nvme-top"
---

# nvme-top(1)

Show live I/O statistics of the NVMe subsystems

## NAME

nvme-top - Show live I/O statistics of the NVMe subsystems

## SYNOPSIS

```
nvme [<global-options>] top [--delay=<seconds> | -d <seconds>]
```

## DESCRIPTION

Shows the subsystems with their I/O rates, refreshed every few seconds, like [top(1)](/top/1.md). Enter shows the namespaces, the paths and the controllers of a subsystem, with their rates, the retries and errors, the multipath failovers and the controller resets and reconnects.

With *--output-format=json*, takes two samples *--delay* seconds apart, prints the rates and the counters as one JSON document, and exits. This is the output for scripts and monitoring tools.

The rates come from the block layer statistics of the namespaces and the paths. A rate is per second, a latency is the average time of an I/O in milliseconds, and the utilization is the share of the interval the device was busy. The rates of a subsystem and a controller are the sum of those of their namespaces or paths, the latency and the utilization the highest of them.

## OPTIONS

- \-d \<seconds\>, --delay=\<seconds\>

  The time between two refreshes, or between the two samples of the JSON output. The default is 1.

## GLOBAL OPTIONS

The following options are defined at the top-level nvme command and are available to this subcommand:

- \--dry-run

  Print the command that would be executed, but do not actually execute it.

- \--no-ioctl-probing

  Disable probing for 64-bit IOCTL support.

- \--no-retries

  Disable retry logic on transient errors.

- \-o \<fmt\>, --output-format=\<fmt\>

  Set the reporting format to *normal*, *tabular, 'json*, or *binary*. Only one output format may be used at a time.

- \--output-format-version=\<version\>

  Select the output format version. Version *1* uses the original field naming, while version *2* (default) provides more consistent and script-friendly field names. Other versions are rejected.

- \--quiet

  Suppress informational messages. Errors are still reported, and --quiet cancels any --verbose for the library log level.

- \--set-options=\<key=value\>\[,\<key=value\>...\]

  Set libnvme library options for this invocation. Supported keys are *force-4k*, *mi-probe-enabled*, *test-base-dir* and *test-sysfs-dir*.

- \--timeout=\<ms\>

  Set the timeout for the command in milliseconds. *infinite* or *-1* waits without a time limit (0xffffffff).

- \-v, --verbose

  Increase the level of detail in the output. May be specified multiple times to further increase verbosity.

These options can also be set as machine-wide defaults in [nvme-cli.conf(5)](/nvme-cli.conf/5.md). A command-line flag always overrides the file.

## JSON OUTPUT

The document has the *Interval* in seconds and a *Subsystems* array. A subsystem has its *Name*, *NQN*, *HostNQN*, *IOPolicy*, *Model*, *Serial*, *Firmware* and *Type*, its *Stats*, a *Namespaces* array and a *Controllers* array.

A namespace of a multipath subsystem has its *Name*, *NSID*, the *RequeueIO* and *FailIO* counts of the I/O which found no usable path, its *Stats* and a *Paths* array. A path has its *Name*, *Controller*, *ANAState*, *NUMANodes*, *Qdepth*, the *Retries*, *Failovers* and *Errors* counts and its *Stats*.

A namespace of a subsystem without multipath has its *Name*, *NSID*, *Controller*, the *Retries* and *Errors* counts and its *Stats*.

A controller has its *Name*, *Transport*, *Address*, *State*, *NUMANode*, the number of *Paths* of a multipath subsystem, the *Resets*, *Reconnects* and *Errors* counts and its *Stats*.

The *Stats* of a namespace or a path are *ReadIOPS*, *WriteIOPS*, *ReadLatencyMs*, *WriteLatencyMs*, *ReadBytesPerSec*, *WriteBytesPerSec*, *Inflights* and *UtilPercent*. Those of a subsystem or a controller have *MaxReadLatencyMs*, *MaxWriteLatencyMs* and *MaxUtilPercent* instead of the latencies and the utilization, and no *Inflights*.

A counter or an attribute the kernel does not provide is left out.

## EXAMPLES

• Watch the subsystems, refreshed every 2 seconds:

```
# nvme top --delay=2
```

• Print the rates over 5 seconds as JSON:

```
# nvme top --delay=5 --output-format=json
```

## NVME

Part of the nvme-user suite