2025-12-23 0

How to Prepare a USB Flash Drive for Cisco Catalyst 9300 and Other Cisco Switches

Introduction

Correctly preparing a USB flash drive is a critical step when managing Cisco Catalyst switches and related network equipment. A properly formatted drive guarantees reliable detection during essential tasks like IOS upgrades, backing up configurations, system recovery, and diagnostic operations.

The engineering team at Telecomate.com underscores the need for accurate USB preparation to prevent compatibility problems and system failures when performing crucial switch procedures.

This manual details the supported file systems for Cisco switches, provides clear formatting steps for Windows, macOS, and Linux, and explains how to verify the drive using the Cisco CLI.

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What Format Does a USB Need to Be for a Cisco Switch?

Cisco Catalyst switches—such as the 9300, 9200, 3850, and 3650 series—work best with USB flash drives formatted in FAT32​ for IOS upgrades and moving configuration files. Older switch models may also accept FAT16. Note that exFAT is typically not a reliable choice for Cisco IOS when performing image upgrades.

For dedicated Cisco USB 3.0 Solid-State Drives (SSDs), like the SSD-240G​ used in Catalyst 9300 platforms, the required file system is EXT4. Cisco also supports EXT3 and EXT2 formats. Avoid NTFS, exFAT, and VFAT as they are incompatible.

The table below outlines file system compatibility for Cisco USB storage:

File System Supported Devices Notes
FAT32 Catalyst 9300/9200/3850/3650 Recommended for standard USB flash drives
FAT16 Older switch models Legacy support only
EXT4 Cisco USB 3.0 SSD (SSD-240G) Required for Catalyst 9300 SSD
exFAT / NTFS Not supported May fail to be recognized during IOS upgrades

What Size USB Drive for Cisco Catalyst 9300?

Cisco Catalyst 9300 switches are compatible with USB flash drives up to 32 GB​ for IOS upgrades and configuration transfers. Drives with larger capacities might sometimes work, but intermittent recognition issues can occur, depending on the IOS version and file system. For the Cisco USB 3.0 SSD, the officially supported capacity is 240 GB (SSD-240G).

Telecomate.com engineers suggest using a 16 GB to 32 GB​ USB drive formatted in FAT32 for optimal stability and consistent detection.

How to Format a USB Flash Drive for Cisco Switches?

Follow these platform-specific guides to prepare your USB drive for Cisco devices.

On Windows

  1. Connect the USB drive to a Windows PC.
  2. Launch File Explorer, go to This PC, right-click the USB drive, and choose Format.
  3. Configure these settings:
    • File System:​ FAT32
    • Allocation Unit Size:​ Default (or 4096 bytes for small files)
    • Volume Label:​ e.g., CISCO_USB
    • Check Quick Format
  4. Click Start​ and confirm the operation.

This prepares the USB drive for transferring IOS images and backing up configurations.

On macOS

  1. Insert the USB drive and open Disk Utility.
  2. Select the USB device itself (not just a partition).
  3. Click Erase​ and configure:
    • Format:​ MS-DOS (FAT)
    • Scheme:​ Master Boot Record (MBR)
    • Name:​ Assign a label (e.g., CISCO_USB)
  4. Click Erase​ to complete the process.

On Linux

Using GParted (Graphical Interface):

  1. Plug in the USB drive.
  2. Open GParted​ and select your USB device.
  3. Unmount any active partitions, delete existing ones, and apply changes.
  4. Create a new partition with the FAT32​ file system and apply.

How to Format Cisco USB 3.0 SSD on Catalyst 9300 (EXT4)?

For the Cisco USB 3.0 SSD (SSD-240G) on Catalyst 9300 switches, format the drive directly via the switch CLI using the EXT4 file system:

For switches in a stack, specify the member number:

This guarantees full compatibility with the SSD-240G module and ensures dependable read/write performance.

How to Verify USB Recognition on Cisco Switches

Once the USB drive is connected and formatted, confirm the switch detects it using these CLI commands:

If the USB drive is not listed, check physical connections or try reseating the device.

Frequently Asked Questions (FAQs)

Q1: What is the required USB format for a Cisco switch?

A1:​ FAT32​ is the most dependable and advised format for Cisco Catalyst switches when upgrading IOS or transferring configurations.

Q2: How do I format a USB drive on Linux for a Cisco switch?

A2:​ Utilize the GParted​ application or the terminal command​ to format your USB drive as FAT32 for Cisco compatibility.

Q3: What USB size works best with a Catalyst 9300?

A3:​ A 16 GB or 32 GB​ USB flash drive provides the ideal mix of sufficient storage and reliable compatibility.

Q4: Do Cisco switches support the FAT32 format?

A4:​ Yes. FAT32​ is fully supported on Cisco Catalyst 9300 and other IOS/IOS XE switches for image transfers and configuration backups.

Troubleshooting USB Flash Drive Not Recognized

If your Cisco switch fails to detect the USB drive, attempt these steps:

  1. Reformat the drive to FAT32​ (or EXT4​ for a Cisco USB 3.0 SSD).
  2. Test with a different USB drive if the problem continues.
  3. Reinsert the USB drive and check for detection again.
  4. Use the command  to list supported devices.

For Cisco USB 3.0 SSDs, also consider these additional checks:

Always check the console logs for any specific error messages if the USB drive is still not recognized.

Best Practices

  • Always back up important data before formatting any USB device.
  • Use the FAT32​ format for general operations with Cisco switches.
  • Use the EXT4​ format for Cisco USB 3.0 SSDs on Catalyst 9300 switches.
  • Unmount Cisco SSDs via the CLI before physically removing them from the switch.
  • Choose 16 GB to 32 GB​ USB drives for the most reliable IOS upgrade experience.
  • Clearly label USB drives for easy identification during large-scale deployments.

Adhering to these best practices helps ensure that IOS upgrades, configuration transfers, and diagnostic activities proceed smoothly, avoiding problems related to USB compatibility.