Create mount-drives.md

Author: jAniceto

programming-notes/linux/mount-drives.md

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+# Mounting external drives
+
+To list all drives run:
+
+```
+$ lsblk
+```
+
+## Mount and unmount external drives
+
+One common need is to mount an external drive, be it an external hard drive, USB stick, or an external SSD.
+
+Create a new mount point, and mount the drive there:
+
+```
+$ sudo mkdir /mnt/externaldrive
+$ sudo mount /dev/sda1 /mnt/externaldrive
+```
+
+To unmount:
+
+```
+$ sudo umount /mnt/externaldrive
+```
+
+
+## Add a new internal drive
+
+### 1) List all drives:
+
+```
+$ lsblk
+```
+
+This will output something like this:
+
+```
+nvme0n1                   259:0    0 953.9G  0 disk
+nvme1n1                   259:1    0 931.5G  0 disk
+├─nvme1n1p1               259:2    0     1G  0 part /boot/efi
+├─nvme1n1p2               259:3    0     2G  0 part /boot
+└─nvme1n1p3               259:4    0 928.5G  0 part
+  └─ubuntu--vg-ubuntu--lv 252:0    0 928.5G  0 lvm  /
+```
+
+In the above we can see `nvme1n1` is partition and mounted at `/`. Another new drive has been added but is still unpartitioned and unmounted.
+
+### 2) If the disk is raw/unpartitioned, we need to partition the new drive:
+
+```
+$ sudo fdisk /dev/nvme0n1
+```
+
+Inside fdisk:
+ - `n` to create new partition
+ - `p` to set as primary
+ - Accept defaults for full disk
+ - `w` to write changes
+
+After this, you should see `/dev/nvme0n1p1`.
+
+### 3) Format the partition for `ext4` (most common case):
+
+```
+$ sudo mkfs.ext4 /dev/nvme0n1p1
+```
+
+Take note of the UUID. We will need it later.
+
+### 4) Create a mount point for the new drive:
+
+```
+$ sudo mkdir -p /mnt/newssd
+```
+
+### 5) Mount the drive (temporarily):
+
+```
+$ sudo mount /dev/nvme0n1p1 /mnt/newssd
+```
+
+You can verify with:
+
+```
+$ df -h
+```
+
+### 6) Get the UUID (required for permanent mount):
+
+```
+$ blkid /dev/nvme0n1p1
+```
+
+It will be something like `UUID="e3b1c9a4-8c5d-4b8d-a9b2-123456789abc"`.
+
+
+### 7) Mount automatically at boot using `fstab`:
+
+```
+$ sudo nano /etc/fstab
+```
+
+Add this line and replace UUID and path:
+
+```
+UUID=e3b1c9a4-8c5d-4b8d-a9b2-123456789abc  /mnt/ssd2  ext4  defaults,nofail  0  2
+```
+
+To test `fstab`:
+
+```
+$ sudo umount /mnt/newssd
+$ sudo mount -a
+```
+
+If no errors, it will mount correctly at boot.
+
+
+### 8) Set permissions so your user can write to it:
+
+```
+$ sudo chown -R $USER:$USER /mnt/newssd
+```