by: Linux/Unix Raspberry Pi

Checking the drives attached to the Linux server or workstation.

  • mount
    • Shows all mounted partitions.
    • Note that it lists much more than physical or virtual volumes. It also includes logical volumes used by the kernel.
  • lsblk
    • Lists all disks as a tree with their partitions and mount points.
  • lsblk -S
    • Lists all disks in a table with additional information such as Brand, Model, Revision, Serial, etc.
  • sudo disktype /dev/sdX
    • Shows detailed information about a disk and its partitions.

FDISK

Popular commands for interactive mode:

  • sudo fdisk /dev/sdX
    • Replace X with the letter the kernel has assigned to the disk.
  1. m
    1. Prints the menu options.
  2. p
    1. Prints the partition table.
  3. d
    1. Deletes a partition. If there is more than one, it will prompt you to select which one.
    2. If there is only one partition, it will be selected automatically.
  4. n
    1. Creates a new partition. It will ask for the partition type: extended or primary (up to 4).
    2. It will then ask where the partition starts (cylinder number) and how large it will be (in KB, MB, GB, or by cylinder).
  5. t
    1. Changes a partition type.
  6. l
    1. Lists known partition types.
  7. F
    1. Lists unallocated space blocks.
  8. g
    1. Wipes the drive and creates a new GPT partition table (recommended).
  9. o
    1. Wipes the drive and creates a new MBR partition table (partitions are limited to 2 TB).
  10. v
    1. Verifies the integrity of the partition table.
  11. i
    1. Prints information about a partition.
  12. w
    1. Writes all changes to the disk and quits.
  13. q
    1. Quits without saving any changes to the disk.
  14. e
    1. Enters expert mode.
      1. i
        1. Changes the disk GUID.
      2. n
        1. Changes the name of a partition.
      3. u
        1. Changes the UUID of a partition.
      4. l
        1. Changes the table length.
      5. A
        1. Flags a legacy BIOS partition as bootable.
      6. p
        1. Prints the partition table with additional information.
      7. r
        1. Returns to the previous menu.

fdisk can also apply changes non-interactively via scripts. See the sfdisk section in the manual for details and examples.

  • sudo fdisk -l
    • Lists all disks attached to the system.

CFDISK

cfdisk does the same thing as fdisk but with a more visual interface. You can navigate partitions and menu options using the arrow keys or keyboard shortcuts.

  • sudo cfdisk /dev/sdX
    • Opens the application on the specified drive.

PARTED

Parted is a powerful partition editor. It also has a graphical version called gparted, which is the default in most GNOME-based distributions.

Important: Changes are written to the disk immediately. There is no separate write step.

  • sudo parted /dev/sdX
    • Opens the application for disk X.
  • sudo parted
    • Opens the application without specifying a disk.
  • help
    • Prints the available options.
  • select /dev/sdX
    • Selects the disk to edit.
  • print
    • Prints the partition table.
  • help mklabel
    • Shows instructions and options for the mklabel command.
  • mklabel gpt
    • Creates a GPT partition table on the disk. Caution: this wipes the entire disk.
  • help mkpart
    • Shows the available options for creating a partition.
  • mkpart
    • Prompts for the required information (partition name, type, start point, end point or size) and creates a new partition.
  • quit
    • Exits the application.

MKFS

Creating a file system (formatting) on a partition.

Once the partition table is created and partitions are defined, each partition needs to be formatted. Formatting creates the chosen file system type on the allocated disk space.

  • sudo mkfs.ext4 -L “PartitionLabel” /dev/sdX1
    • Formats partition 1 on disk X as EXT4 (recommended) with a label.
    • The same command structure applies to:
      • mkfs.vfat
      • mkfs.fat (outdated)
      • mkfs.ntfs (modern Windows partition)
      • mkfs.ext3 (outdated)
      • mkfs.ext2 (outdated)
      • mkfs.bfs
      • …

MOUNTING VOLUMES

Mounting volumes on boot:

ls -l /dev/disk/by-uuid/
sudo nano /etc/fstab

Append a line using one of these formats:

UUID=0e5accff-ddcb-46ac-bd52-94719086959b /mounting_point ext4 defaults 0 0

OR

/dev/sdb1 /mounting_point ext4 defaults 0 0

Apply changes without rebooting:

sudo mount -a

TUNING THE FILESYSTEM

tune2fs allows you to adjust ext2/ext3/ext4 filesystem parameters [Link]. It gives Linux administrators control over key parameters that affect the health and reliability of the system.

  • -l
    • Displays the file system structure and current parameter values.
  • -L
    • Sets the volume label of the file system.
  • -c
    • Sets the maximum mount count before the file system is checked for errors.
  • -O
    • Enables or disables specific file system features.
  • -r
    • Sets the number of reserved blocks.
sudo tune2fs -l /dev/nvme0n1p1
sudo tune2fs -L "New Label" /dev/nvme0n1p1
sudo tune2fs -c 35 /dev/nvme0n1p1
sudo tune2fs -O dir_index /dev/nvme0n1p1
sudo tune2fs -r 5 /dev/nvme0n1p1