DiagnosticsEXEC

show hardware

Displays hardware inventory, status, and environmental information for Cisco Nexus switches.

Overview

The 'show hardware' command on Cisco NX-OS (Nexus) provides comprehensive information about the physical components and environmental status of the switch. It is essential for hardware inventory management, environmental monitoring, and troubleshooting hardware-related issues. The command has several subcommands: 'show hardware inventory' lists all field-replaceable units (FRUs) such as chassis, modules, power supplies, and fans with their part numbers and serial numbers. 'show hardware environment' displays temperature sensors, fan speeds, and power supply status. 'show hardware module' shows the operational status of each module (line card, supervisor). 'show hardware system-resources' reports CPU and memory utilization. 'show hardware capacity' provides information about hardware resource usage like TCAM and forwarding tables. This command is used during initial deployment to verify correct hardware installation, during routine maintenance to check environmental conditions, and during troubleshooting to identify failed components. On Nexus platforms, the output is structured and consistent across models, but specific sensor names and thresholds may vary. Understanding this command is crucial for network engineers to ensure hardware reliability and to quickly isolate faulty components.

Syntax·EXEC

show hardware [capacity | environment | inventory | module | system-resources]

When to Use This Command

Verify hardware components (line cards, power supplies, fans) are present and operational after installation.
Check environmental parameters like temperature, voltage, and fan speed to prevent overheating.
Troubleshoot hardware failures by examining module status and error counters.
Assess system resource utilization (CPU, memory) for capacity planning.

Parameters

Parameter	Syntax	Required	Description
capacity	show hardware capacity	Optional	Displays hardware resource utilization such as TCAM, FIB, and MAC table usage. Useful for capacity planning.
environment	show hardware environment [temperature \| fan \| power]	Optional	Shows environmental status. Without sub-option, displays all. 'temperature' shows sensor readings, 'fan' shows fan speeds, 'power' shows power supply status.
inventory	show hardware inventory	Optional	Lists all hardware components with PID, VID, and serial numbers. Essential for asset management and RMA.
module	show hardware module [slot-number]	Optional	Displays module status, uptime, and hardware revision. Specify slot number for a specific module.
system-resources	show hardware system-resources	Optional	Shows CPU and memory utilization percentages. Useful for performance monitoring.

Command Examples

Show hardware inventory

show hardware inventory

Name: "Chassis",  descr: "Nexus 9000 Series Chassis"
PID: N9K-C93180YC-FX3   ,  VID: V01  ,  SN: FOC12345678

Name: "Module 1",  descr: "48x10/25G + 6x40/100G Ethernet Module"
PID: N9K-X97160YC-EX   ,  VID: V02  ,  SN: FOC87654321

Name: "Fan 1",  descr: "Fan Module"
PID: N9K-C9300-FAN      ,  VID: V01  ,  SN: FAN12345678

Name: "Power Supply 1",  descr: "AC Power Supply"
PID: N9K-PAC-650W       ,  VID: V01  ,  SN: PSU12345678

Lists all hardware components with Product ID (PID), Version ID (VID), and Serial Number (SN). Useful for inventory management and RMA.

Show hardware environment

show hardware environment temperature

Module 1: Temperature: 45 C (Normal)
Module 2: Temperature: 52 C (Normal)
Fan 1: Speed: 8000 RPM (Normal)
Fan 2: Speed: 8100 RPM (Normal)
Power Supply 1: Status: OK
Power Supply 2: Status: OK

Displays temperature, fan speed, and power supply status. Healthy values show 'Normal' or 'OK'. High temperatures or fan failures indicate potential hardware issues.

Understanding the Output

The 'show hardware' command output varies by subcommand. For 'show hardware inventory', each component is listed with its name, description, PID, VID, and SN. PID identifies the exact model, VID indicates revision, and SN is unique for RMA. For 'show hardware environment', temperature is shown in Celsius with a status (Normal, Warning, Critical). Fan speed in RPM and power supply status (OK, Fault) are also displayed. Healthy values are within normal ranges; warnings or criticals require immediate attention. The 'show hardware module' output includes module status (ok, failed, power-deny) and uptime. 'show hardware system-resources' shows CPU and memory utilization percentages.

Configuration Scenarios

Verifying Hardware After Installation

After installing a new line card in a Nexus 9000 switch, verify it is recognized and operational.

Topology

[Nexus 9000 Chassis]
  Slot 1: Supervisor
  Slot 2: New Line Card (N9K-X97160YC-EX)
  Slot 3: Existing Line Card

Steps

1.Connect to the switch via console or SSH.
2.Enter EXEC mode.
3.Run 'show hardware inventory' to confirm the new module appears with correct PID and SN.
4.Run 'show hardware module 2' to check status (should be 'ok').

Configuration

! No configuration needed; verification only.

Verify: Output of 'show hardware module 2' shows status 'ok' and uptime increasing. 'show hardware inventory' lists the module with correct PID.

Watch out: If the module status shows 'power-deny', check power budget and ensure power supplies have enough capacity.

Troubleshooting with This Command

When a Nexus switch experiences hardware issues, 'show hardware' commands are the first step. If a module fails, 'show hardware module' will show status 'failed' or 'power-deny'. Check 'show hardware environment temperature' for overheating; if a sensor shows 'Critical', inspect fans and airflow. For fan failures, 'show hardware environment fan' will show 'Fault'. Power supply issues appear in 'show hardware environment power' as 'Fault' or 'Not Present'. Use 'show hardware inventory' to get serial numbers for RMA. If CPU or memory is high, 'show hardware system-resources' helps identify resource exhaustion. For intermittent issues, monitor 'show hardware environment' over time. Always correlate with logs using 'show logging last 10' to see hardware-related messages. On Nexus, hardware errors may also appear in 'show module' output. If a module repeatedly fails, consider reseating it. For environmental alarms, ensure proper cooling and power redundancy.

CCNA Exam Tips

Know that 'show hardware inventory' is used to verify correct hardware installation and serial numbers for RMA.

Remember that 'show hardware environment temperature' is critical for monitoring thermal health; normal ranges vary by platform.

Understand that 'show hardware module' helps identify failed modules; status 'ok' is healthy, 'failed' indicates a fault.

Common Mistakes

Mistake: Using 'show hardware' without a subcommand, which may not show desired details. Consequence: Incomplete information; always use specific subcommand.

Mistake: Ignoring temperature warnings assuming they are temporary. Consequence: Overheating can cause switch shutdown or hardware damage.

Mistake: Confusing PID with SN when ordering replacements. Consequence: Wrong part ordered; always verify PID.

Platform Notes

On Cisco NX-OS (Nexus), 'show hardware' is similar to 'show inventory' and 'show environment' on Cisco IOS, but with more detailed subcommands. Nexus uses 'show hardware inventory' instead of 'show inventory all' on IOS. The 'show hardware environment' command on Nexus provides granular sensor data, whereas IOS uses 'show environment all'. On Nexus 9000 series, temperature thresholds are pre-defined and cannot be changed. On older Nexus 5000/7000, some subcommands may differ slightly. For example, 'show hardware capacity' on Nexus 9000 shows TCAM utilization, while on Nexus 7000, 'show hardware capacity' may show different resource pools. Always refer to the specific platform documentation. Equivalent commands on other vendors: Juniper uses 'show chassis hardware', Arista uses 'show inventory'. For environmental monitoring, Juniper uses 'show chassis environment', Arista uses 'show system environment'. Understanding these differences helps multi-vendor environments.

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