NVMe

This section introduces how to use the NVMe hard drive function on the Raspberry Pi, laying the foundation for subsequent project development.

Note: The PCIe interface must be enabled before using this function.

Enable PCIe Interface

If the PCIe interface is not enabled, enable the PCIe interface first
Check supported formats. Type sudo mkfs. and press the tab key to see various suffixes corresponding to different format types
```
sudo mkfs.
```
List all drives
```
lsblk
```
To format /dev/nvme0n1p1 as ext4, for example, execute:
```
sudo mkfs.ext4 /dev/nvme0n1p1
```

If the PCIe interface is not enabled, enable the PCIe interface first
List all drives (use sudo fdisk -l for detailed information)
```
lsblk
```
To repartition /dev/nvme0n1, execute the following command (Note: Use the main device number, not a partition like p1):
```
sudo fdisk /dev/nvme0n1
```
Press n to add a new partition, and finally w to save and exit
fdisk command functions:
- n Create a new partition
- q Quit without saving
- p Print the partition table
- m Print the menu
- d Delete a partition
- w Write table to disk and exit
- t Change a partition's system ID

If the PCIe interface is not enabled, enable the PCIe interface first
Confirm the mount directory. Create the directory if it doesn't exist (e.g., to mount to a toshiba folder in the current directory, create it if missing):
```
sudo mkdir toshiba
```
List all drives (use sudo fdisk -l for detailed information)
```
lsblk
```
To mount /dev/nvme0n1 to the toshiba folder in the current directory, for example:
```
sudo mount /dev/nvme0n1p1 ./toshiba
```
Check the file system disk space usage
```
df -h
```

Note: Auto-mounting is only used when the drive is not the system disk, i.e., when it functions as additional storage. Perform this configuration only in such cases
If the PCIe interface is not enabled, enable the PCIe interface first
Modify the fstab file
```
sudo nano /etc/fstab
```
Add the following line at the end of the file (/dev/nvme0n1p1: device name, /home/pi/toshiba: mount directory, ext4: ilesystem type, defaults uses standard mount options)
```
/dev/nvme0n1p1  /home/pi/toshiba  ext4  defaults  0  0
```
Apply the changes (Test the mount first to avoid boot issues if the mount fails)
```
sudo mount -a
```
If no errors occur, reboot the system
```
sudo reboot
```
After reboot, verify the mount status
```
lsblk
```

If the PCIe interface is not enabled, enable the PCIe interface first
Check the mount status
```
lsblk
```
If mounted correctly, navigate to the mount directory (here /home/pi/toshiba)
```
cd /home/pi/toshiba
```

Copy data from Raspberry Pi memory to the drive (Write Test)

sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"   # Clear memory caches
sudo dd if=/dev/zero of=./test_write count=2000 bs=1024k  # Write test

List all drives

Copy data from the drive to Raspberry Pi memory (Read Test)

sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"   # Clear memory caches
sudo dd if=./test_write of=/dev/null count=2000 bs=1024k  # Read test

List all drives

Note: Performance varies depending on the drive and the environment on the Raspberry Pi. Some drives may be speed-limited. For accurate performance testing, use a PC