Skip to main content

Command documentation sourced from the linux-command project This comprehensive command reference is part of the linux-command documentation project.

lsblk - List Block Devices

The lsblk command lists information about all available block devices and displays their relationships in a tree-like structure. It's an essential tool for system administrators to view disk partitions, storage devices, and their mount points.

Basic Syntax​

lsblk [options] [device...]

Common Options​

Display Options​

  • -a, --all - Show all devices including empty devices
  • -b, --bytes - Print sizes in bytes instead of human-readable format
  • -d, --nodeps - Don't print slaves or holders (show only parent devices)
  • -l, --list - Use list format instead of default tree format
  • -n, --noheadings - Don't print column headings
  • -P, --pairs - Use key="value" output format
  • -r, --raw - Use raw output format
  • -t, --topology - Show topology information

Information Options​

  • -f, --fs - Show filesystem information
  • -m, --perms - Show permissions information
  • -o, --output <list> - Specify output columns
  • -D, --discard - Show discard capabilities

Filtering Options​

  • -e, --exclude <list> - Exclude devices (default: RAM disks)
  • -I, --include <list> - Show only devices with specified major numbers

Other Options​

  • -h, --help - Display help message
  • -V, --version - Display version information

Usage Examples​

Basic Device Listing​

# Show all block devices in tree format
lsblk

# Typical output:
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 238.5G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
├─sda2   8:2    0 238.0G  0 part /
└─sda3   8:3    0     1K  0 part
sdb      8:16   0 931.5G  0 disk
└─sdb1   8:17   0 931.5G  0 part /data
sr0     11:0    1  1024M  0 rom

Show Filesystem Information​

# Display filesystem details
lsblk -f

# Output includes filesystem type, UUID, and mount point
NAME   FSTYPE   LABEL       UUID                                 FSAVAIL FSUSE% MOUNTPOINT
sda
├─sda1 vfat     SYSTEM      XXXX-XXXX                             511.9M     1% /boot/efi
├─sda2 ext4                 XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX  214.2G    10% /
└─sda3
sdb
└─sdb1 ext4     DATA        XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX  890.3G     4% /data
sr0

Show All Devices Including Empty​

# List all devices, including empty ones
lsblk -a

# This shows devices that might not have partitions

List Format Output​

# Display in list format instead of tree
lsblk -l

# Output in tabular format:
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 238.5G  0 disk
sda1     8:1    0   512M  0 part /boot/efi
sda2     8:2    0 238.0G  0 part /
sdb      8:16   0 931.5G  0 disk
sdb1     8:17   0 931.5G  0 part /data

Show Permissions​

# Display device permissions
lsblk -m

# Output includes owner, group, and mode:
NAME      SIZE OWNER GROUP MODE
sda     238.5G root  disk  brw-rw----
sda1       512M root  disk  brw-rw----
sda2     238.0G root  disk  brw-rw----

Custom Output Columns​

# Specify specific columns to display
lsblk -o NAME,SIZE,TYPE,MOUNTPOINT,UUID

# Available columns include:
# NAME, KNAME, PATH, MAJ:MIN, FSTYPE, MOUNTPOINT
# LABEL, UUID, PARTUUID, RA, RO, RM, MODEL, SIZE
# STATE, OWNER, GROUP, MODE, ALIGNMENT, MIN-IO
# OPT-IO, PHY-SEC, LOG-SEC, ROTA, SCHED, RQ-SIZE
# TYPE, DISC-ALN, DISC-GRAN, DISC-MAX, DISC-ZERO

Size in Bytes​

# Show exact sizes in bytes
lsblk -b

# Useful for scripts and precise calculations
lsblk -b -o NAME,SIZE

Show Device Topology​

# Display topology information
lsblk -t

# Shows alignment, minimum IO size, physical sector, etc.

Practical Examples​

Disk Usage Analysis​

# Check disk usage and identify large partitions
lsblk -f -o NAME,FSTYPE,SIZE,MOUNTPOINT,USE%

# Show which disks are getting full
df -h | while read line; do
    if [[ $line =~ ^/dev/ ]]; then
        device=$(echo $line | cut -d' ' -f1)
        mount_point=$(echo $line | cut -d' ' -f6)
        usage=$(echo $line | awk '{print $5}')
        if [[ ${usage%?} -gt 80 ]]; then
            echo "Warning: $device ($mount_point) is ${usage} full"
        fi
    fi
done

Identify Available Storage​

# Find unmounted partitions
lsblk -f | grep -E "(part|disk)" | grep -v "MOUNTPOINT"

# Show available space on mounted filesystems
lsblk -f -o NAME,SIZE,FSAVAIL,MOUNTPOINT

Storage Device Inventory​

# Get detailed inventory of all storage devices
lsblk -d -o NAME,SIZE,MODEL,VENDOR,ROTA,STATE

# Output includes:
# NAME    SIZE MODEL                    VENDOR  ROTA STATE
# sda   238.5G SSD                      KINGSTON    0 running
# sdb   931.5G ST1000LM035-1RK1        SEAGATE     1 running

Scripting and Automation​

# Get list of all disk devices
lsblk -d -n -o NAME | grep -E '^sd|^nvme|^vd|^hd'

# Find all partitions of a specific disk
lsblk -n -l -o NAME /dev/sda | tail -n +2

# Check if a device is a solid state drive
lsblk -d -n -o NAME,ROTA | grep -w '0$' | cut -d' ' -f1

# Get mount points for a specific device
lsblk -n -o MOUNTPOINT /dev/sda2 | grep -v '^$'

Storage Performance Information​

# Check if devices are rotational (HDD) or solid state (SSD)
lsblk -d -o NAME,ROTA,MODEL

# ROTA=1 means rotational (HDD), ROTA=0 means non-rotational (SSD)

Device Verification​

# Verify device exists and get its properties
if lsblk /dev/sda >/dev/null 2>&1; then
    echo "Device /dev/sda exists:"
    lsblk -f /dev/sda
else
    echo "Device /dev/sda not found"
fi

Advanced Usage​

Monitoring Storage Changes​

# Monitor for storage device changes
watch -n 1 'lsblk -f'

# Show changes in real-time
lsblk -f > /tmp/lsblk_before.txt
# After making changes
lsblk -f > /tmp/lsblk_after.txt
diff /tmp/lsblk_before.txt /tmp/lsblk_after.txt

Working with LVM and RAID​

# Show LVM volumes and physical volumes
lsblk -f

# Display RAID array information
lsblk -d -o NAME,SIZE,TYPE

# Show all block devices including MD RAID
cat /proc/mdstat
lsblk -f

USB and External Storage​

# Identify USB storage devices
lsblk -d -o NAME,MODEL,VENDOR | grep -i usb

# Show removable devices
lsblk -d -o NAME,RM | grep ': 1$'

# Hot-plug detection
lsblk -f > /tmp/devices_before
# Plug in USB device
lsblk -f > /tmp/devices_after
diff /tmp/devices_before /tmp/devices_after

Virtualization and Container Storage​

# Show loop devices (often used for containers/images)
lsblk -f | grep loop

# Display device mapper targets
lsblk -f | grep dm

# List all block devices with their types
lsblk -o NAME,TYPE,SIZE

Output Columns Reference​

Device Identification​

  • NAME - Device name
  • KNAME - Kernel device name
  • PATH - Device path
  • MAJ:MIN - Major and minor device numbers

Device Properties​

  • SIZE - Size of device
  • TYPE - Device type (disk, part, rom, etc.)
  • MODEL - Device model name
  • VENDOR - Device vendor
  • SERIAL - Serial number
  • STATE - Device state (running, offline)

Filesystem Information​

  • FSTYPE - Filesystem type
  • MOUNTPOINT - Where the device is mounted
  • LABEL - Filesystem label
  • UUID - Universally Unique Identifier
  • PARTUUID - Partition UUID

Performance and Capabilities​

  • ROTA - Rotational flag (1=HDD, 0=SSD)
  • RO - Read-only flag
  • RM - Removable flag
  • ALIGNMENT - Alignment offset
  • MIN-IO - Minimum I/O size
  • OPT-IO - Optimal I/O size
  • PHY-SEC - Physical sector size
  • LOG-SEC - Logical sector size

Permissions​

  • OWNER - Device owner
  • GROUP - Device group
  • MODE - Device permissions
  • DISC-GRAN - Discard granularity
  • DISC-MAX - Maximum discard size
  • fdisk - Partition table manipulator
  • parted - Disk partitioning utility
  • df - Display free disk space
  • du - Display disk usage statistics
  • mount - Mount filesystems
  • umount - Unmount filesystems
  • blkid - Locate/print block device attributes

Troubleshooting​

Common Issues​

Device Not Listed​

# Check if device exists
ls /dev/sd*

# Rescan SCSI bus
echo "- - -" > /sys/class/scsi_host/host0/scan

# Check kernel messages for device detection
dmesg | grep -i scsi
dmesg | grep -i usb

Permission Denied​

# Run with sudo for complete information
sudo lsblk -f

# Add user to disk group for non-root access
sudo usermod -a -G disk $USERNAME

Missing Filesystem Information​

# Sometimes fsck is needed to detect filesystems
sudo fsck /dev/sda1

# Force filesystem table update
sudo partprobe /dev/sda

Incorrect Size Display​

# Check real device size
sudo blockdev --getsize64 /dev/sda

# Verify sector sizes
sudo blockdev --getss /dev/sda
sudo blockdev --getpbsz /dev/sda

Best Practices​

  1. Use lsblk -f for comprehensive filesystem information
  2. Run with sudo to see all available information
  3. Use -b option for scripting to avoid parsing human-readable sizes
  4. Combine with watch for monitoring storage changes
  5. Regular inventory using lsblk -d -o NAME,SIZE,MODEL for asset tracking
  6. Check ROTA field to distinguish between SSDs and HDDs
  7. Use UUIDs instead of device names in /etc/fstab for persistence

The lsblk command is an indispensable tool for Linux system administration, providing a comprehensive view of all block devices and their relationships in an easy-to-understand format.

Sponsors:DigitalOceanVultrSetappCloudflare