Introduction
This article will explore the 'lsblk' command to understand the structure of storage devices through practical examples with filtering options. This will help you manage, monitor, analyze, and troubleshoot block devices on a Linux system. Block devices are storage devices that store and retrieve data in fixed-size blocks.
Installation
To install 'lsblk', you can refer to the following commands base on your Linux distro:
On Debian/Ubuntu
$sudo apt-get install util-linux
On CentOS/RedHat
$sudo yum install util-linux-ng
Using the lsblk command with examples
The 'lsblk' command is the tool that can be used to retrieve information about storage devices and attributes, such as device names, sizes, labels, file systems, mount points, owner, etc.
1. Display block device
By running lsblk command only without any options, output will list block devices, with their names, sizes, type and mount point. For example:
$ lsblk
Sample output
jayce@Ubuntu-01:~$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 4K 1 loop /snap/bare/5 loop1 7:1 0 302.3M 1 loop /snap/code/131 loop2 7:2 0 302.3M 1 loop /snap/code/132 loop3 7:3 0 116.8M 1 loop /snap/core/14946 loop4 7:4 0 118.2M 1 loop /snap/core/15419 loop5 7:5 0 55.6M 1 loop /snap/core18/2751 loop6 7:6 0 55.7M 1 loop /snap/core18/2785 loop7 7:7 0 63.5M 1 loop /snap/core20/1891 loop8 7:8 0 63.4M 1 loop /snap/core20/1950 loop9 7:9 0 73.8M 1 loop /snap/core22/750 loop10 7:10 0 73.9M 1 loop /snap/core22/766 loop11 7:11 0 240.6M 1 loop /snap/firefox/2356 loop12 7:12 0 349.7M 1 loop /snap/gnome-3-38-2004/137 loop13 7:13 0 239.9M 1 loop /snap/firefox/2487 loop14 7:14 0 349.7M 1 loop /snap/gnome-3-38-2004/140 loop15 7:15 0 460.7M 1 loop /snap/gnome-42-2204/105 loop16 7:16 0 466.5M 1 loop /snap/gnome-42-2204/111 loop17 7:17 0 91.7M 1 loop /snap/gtk-common-themes/1535 loop18 7:18 0 11.7M 1 loop /snap/kubectl/2963 loop19 7:19 0 45.9M 1 loop /snap/snap-store/638 loop20 7:20 0 11.7M 1 loop /snap/kubectl/2987 loop21 7:21 0 12.3M 1 loop /snap/snap-store/959 loop22 7:22 0 53.3M 1 loop /snap/snapd/19361 loop23 7:23 0 53.3M 1 loop /snap/snapd/19457 loop24 7:24 0 304K 1 loop /snap/snapd-desktop-integration/49 loop25 7:25 0 452K 1 loop /snap/snapd-desktop-integration/83 sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 513M 0 part /boot/efi └─sda3 8:3 0 49.5G 0 part ├─vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] sr0 11:0 1 3.6G 0 rom
2. Exclude the loop devices
Note the lots of loop devices that appear on ubuntu based systems using snap package system. If you want to hide all the loop devices use the "-e7" option with lsblk like this:
$ lsblk -e7
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 111.8G 0 disk
└─sda1 8:1 0 95.4G 0 part /var/snap/firefox/common/host-hunspell
/
sdb 8:16 0 111.8G 0 disk
└─sdb1 8:17 0 95.8G 0 part [SWAP]
sdc 8:32 0 447.1G 0 disk
└─sdc1 8:33 0 400G 0 part /media/enlightened/a935afc9-17fd-4de1-8012-137e82662ff0
sde 8:64 0 0B 0 disk
$
The e option basically excludes devices of the specified major number.
3. Listing all devices
With option '-a' or '--all', the output will print all devices, including empty devices, as in the following example:
$ lsblk -a
Sample output
jayce@Ubuntu-01:~$ lsblk -a -e7 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 513M 0 part /boot/efi └─sda3 8:3 0 49.5G 0 part ├─vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] sr0 11:0 1 3.6G 0 rom
4. Display size column in byte format
If you do not like readable size format, you can use '-b' or ' --bytes' option to display output size format in bytes.
$ lsblk -b
Sample output
jayce@Ubuntu-01:~$ lsblk -b NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 4096 1 loop /snap/bare/5 loop1 7:1 0 317022208 1 loop /snap/code/131 loop2 7:2 0 317026304 1 loop /snap/code/132 sda 8:0 0 53687091200 0 disk ├─sda1 8:1 0 1048576 0 part ├─sda2 8:2 0 537919488 0 part /boot/efi └─sda3 8:3 0 53146025984 0 part ├─vgubuntu-root 253:0 0 49199185920 0 lvm /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 253:1 0 3896508416 0 lvm [SWAP] sr0 11:0 1 3826831360 0 rom
5. Display information about filesystems
To output information about UUID (unique ID), device labels, mount points, file system types, etc., use the '-f' or '--fs' option.
$ lsblk -f
Sample output
jayce@Ubuntu-01:~$ lsblk -f NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS loop0 squashfs 4.0 0 100% /snap/bare/5 loop1 squashfs 4.0 0 100% /snap/code/131 sda ├─sda1 ├─sda2 vfat FAT32 7C04-B053 506.7M 1% /boot/efi └─sda3 LVM2_member LVM2 001 3uPfc3-rtSZ-FMbH-PKAo-E7p9-UmiN-53qoJT ├─vgubuntu-root ext4 1.0 fd23872b-bbb8-4bb3-b7b9-425ed0ae0308 21.6G 47% /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 swap 1 9d3263eb-474e-4aea-a596-93a164093a9c [SWAP] sr0 iso9660 Joliet Extension Ubuntu 22.04.1 LTS amd64 2022-08-10-16-21-45-00
6. Use ASCII characters
You can use '-i' or '--ascii' option to output ASCII characters formatting.
$ lsblk -i
Sample output
jayce@Ubuntu-01:~$ lsblk -i NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 4K 1 loop /snap/bare/5 loop1 7:1 0 302.3M 1 loop /snap/code/131 loop2 7:2 0 302.3M 1 loop /snap/code/132 loop3 7:3 0 116.8M 1 loop /snap/core/14946 loop4 7:4 0 118.2M 1 loop /snap/core/15419 loop5 7:5 0 55.6M 1 loop /snap/core18/2751 sda 8:0 0 50G 0 disk |-sda1 8:1 0 1M 0 part |-sda2 8:2 0 513M 0 part /boot/efi `-sda3 8:3 0 49.5G 0 part |-vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell | / `-vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] sr0 11:0 1 3.6G 0 rom
7. Output information about block-device topology
To display the device block topology, use 'lsblk' command along with option '-t' or '--topology'.
$ lsblk -t
Sample output
jayce@Ubuntu-01:~$ lsblk -t NAME ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE RA WSAME loop0 0 512 0 512 512 1 none 128 128 0B loop1 0 512 0 512 512 1 none 128 128 0B loop2 0 512 0 512 512 1 none 128 128 0B sda 0 512 0 512 512 1 mq-deadline 254 128 0B ├─sda1 0 512 0 512 512 1 mq-deadline 254 128 0B ├─sda2 0 512 0 512 512 1 mq-deadline 254 128 0B └─sda3 0 512 0 512 512 1 mq-deadline 254 128 0B ├─vgubuntu-root 0 512 0 512 512 1 128 128 0B └─vgubuntu-swap_1 0 512 0 512 512 1 128 128 0B sr0 0 2048 0 2048 2048 1 mq-deadline 64 128 0B
8. Display list format instead of tree format
The 'lsblk' command will display the output in a tree format. However, you can change it to list format by using the '-l' or '--list' option.
$ lsblk -l
Sample output
jayce@Ubuntu-01:~$ lsblk -l
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 4K 1 loop /snap/bare/5
loop1 7:1 0 302.3M 1 loop /snap/code/131
loop2 7:2 0 302.3M 1 loop /snap/code/132
loop3 7:3 0 116.8M 1 loop /snap/core/14946
loop4 7:4 0 118.2M 1 loop /snap/core/15419
loop5 7:5 0 55.6M 1 loop /snap/core18/2751
sda 8:0 0 50G 0 disk
sda1 8:1 0 1M 0 part
sda2 8:2 0 513M 0 part /boot/efi
sda3 8:3 0 49.5G 0 part
sr0 11:0 1 3.6G 0 rom
vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell
/
vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP]
9. Excluding the devices specified by the comma-separated list of major device numbers
With the '-e' or '--exclude' option, the output will exclude block devices by major type.
For example, if the major node type of 'loop' block device is '7', and you want to exclude it from the output, use the following command:
$ lsblk -e [major-value]
Sample output
jayce@Ubuntu-01:~$ lsblk -e 7 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 513M 0 part /boot/efi └─sda3 8:3 0 49.5G 0 part ├─vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] sr0 11:0 1 3.6G 0 rom
10. Display specific columns only
With option '-o' or '--output', it will display specific columns that you want to list.
For example, to display only the NAME, SERIAL, MODEL, TYPE, SIZE and MOUNTPOINT of block devices, you can use the following command:
$ lsblk --output NAME,SERIAL,MODEL,TYPE,SIZE,MOUNTPOINT
Sample output
jayce@Ubuntu-01:~$ lsblk --output NAME,SERIAL,MODEL,TYPE,SIZE,MOUNTPOINT NAME SERIAL MODEL TYPE SIZE MOUNTPOINT loop0 loop 4K /snap/bare/5 loop1 loop 302.3M /snap/code/131 loop2 loop 302.3M /snap/code/132 sda VMware Virtual S disk 50G ├─sda1 part 1M ├─sda2 part 513M /boot/efi └─sda3 part 49.5G ├─vgubuntu-root lvm 45.8G / └─vgubuntu-swap_1 lvm 3.6G [SWAP] sr0 01000000000000000001 VMware Virtual SATA CDRW Drive rom 3.6G
Here is my favorite way of doing it to display details about all the storage drives on the system, whether internal ssd, usb drives, external hdds and ssds.
$ lsblk -e7 -o "NAME,PTTYPE,FSTYPE,SIZE,LABEL,PARTLABEL,PATH,PHY-SEC,VENDOR" NAME PTTYPE FSTYPE SIZE LABEL PARTLABEL PATH PHY-SEC VENDOR sda dos 111.8G /dev/sda 512 ATA └─sda1 dos ext4 95.4G /dev/sda1 512 sdb dos 111.8G /dev/sdb 512 ATA └─sdb1 dos swap 95.8G /dev/sdb1 512 sdc gpt 447.1G /dev/sdc 512 ATA └─sdc1 gpt ext4 400G /dev/sdc1 512 sdd dos 465.8G /dev/sdd 512 Samsung └─sdd1 dos ext4 420G /dev/sdd1 512 sde 0B /dev/sde 512 Seagate $
The vendor ATA simply means that the drive is connected via a SATA (mostly internal) cable on the motherboard. Whereas the Samsung, and Seagate drives are external portable SSDs and HDDs respectively.
11. Checking whether it is a SSD or Hard Disk Drive (HDD)
To find out what is SSD or Hard Disk Drive, use the following command:
$ lsblk --output +ROTA,DISC-GRAN
Sample output
jayce@Ubuntu-01:~$ lsblk --output +ROTA,DISC-GRAN NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS ROTA DISC-GRAN loop0 7:0 0 4K 1 loop /snap/bare/5 1 0B loop1 7:1 0 302.3M 1 loop /snap/code/131 1 0B loop2 7:2 0 302.3M 1 loop /snap/code/132 1 0B sda 8:0 0 50G 0 disk 1 0B ├─sda1 8:1 0 1M 0 part 1 0B ├─sda2 8:2 0 513M 0 part /boot/efi 1 0B └─sda3 8:3 0 49.5G 0 part 1 0B ├─vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell 1 0B │ / └─vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] 1 0B sr0 11:0 1 3.6G 0 rom 1 0B
- ROTA: this column will show whether or not a block device belongs to a rotational storage device. Hard disk drive can spin, so this column outputs the value '1' (a binary logical value means 'true').
- DISC-GRAN: this column will show the discard granularity. SSDs support discarding to free up unused data blocks, HDD don't support this feature, so it normally will show no discard capabilities '0B'.
12. Display without slave or holders entries
You can use '-d' or '--nodeps' option to remove all the child devices in the output. It just displays the devices that you provided and doesn't include their partitions, etc.
Run the following command to output information about the 'sda' device only.
$ lsblk -d /dev/sda –output
Sample output
jayce@Ubuntu-01:~$ lsblk -d /dev/sda –output NAME,PTTYPE,FSTYPE,TYPE,SIZE,MOUNTPOINT NAME PTTYPE FSTYPE TYPE SIZE MOUNTPOINT sda gpt disk 50G
13. Displaying zone model for devices
The zone model of a block storage device can be discovered by option '-z' or '--zoned'. There are some possible values of the zoned model attributes, which are none, host-aware, host-managed.
$ lsblk -z
Sample output
jayce@Ubuntu-01:~$ lsblk -z NAME ZONED loop0 none loop1 none loop2 none sda none ├─sda1 none ├─sda2 none └─sda3 none ├─vgubuntu-root none └─vgubuntu-swap_1 none sr0 none
14. Display information about device owner, group, and mode of block devices
To output information about permissions of block devices, use options '-m' or '--perms'.
$ lsblk -m
Sample output
jayce@Ubuntu-01:~$ lsblk -m NAME SIZE OWNER GROUP MODE loop0 4K root disk brw-rw---- loop1 302.3M root disk brw-rw---- loop2 302.3M root disk brw-rw---- loop3 116.8M root disk brw-rw---- loop4 118.2M root disk brw-rw---- loop5 55.6M root disk brw-rw---- sda 50G root disk brw-rw---- ├─sda1 1M root disk brw-rw---- ├─sda2 513M root disk brw-rw---- └─sda3 49.5G root disk brw-rw---- ├─vgubuntu-root 45.8G root disk brw-rw---- └─vgubuntu-swap_1 3.6G root disk brw-rw---- sr0 3.6G root cdrom brw-rw----
15. Hiding column headings
To exclude column heading when printing output, use option '-n' or '--noheadings'.
$ lsblk -n
Sample output
jayce@Ubuntu-01:~$ lsblk -n loop0 7:0 0 4K 1 loop /snap/bare/5 loop1 7:1 0 302.3M 1 loop /snap/code/131 loop2 7:2 0 302.3M 1 loop /snap/code/132 loop3 7:3 0 116.8M 1 loop /snap/core/14946 loop4 7:4 0 118.2M 1 loop /snap/core/15419 loop5 7:5 0 55.6M 1 loop /snap/core18/2751 sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 513M 0 part /boot/efi └─sda3 8:3 0 49.5G 0 part ├─vgubuntu-root 253:0 0 45.8G 0 lvm /var/snap/firefox/common/host-hunspell │ / └─vgubuntu-swap_1 253:1 0 3.6G 0 lvm [SWAP] sr0 11:0 1 3.6G 0 rom
16. Display block devices which are NOT in-use
If you want to identify block devices which are not in-use, you can combine 'lsblk' with option '-T' or '--tree' and 'jq' command. It is used to transform JSON data into a more readable format and display it to the standard output.
Run the following command to check which block devices and their children have no mount points.
$ lsblk --tree -o PATH,MOUNTPOINT -J | jq -r '.blockdevices[] | del(select(.mountpoint!=null or .children[]?.mountpoint!=null)) | .path // empty'
Sample output
jayce@Ubuntu-01:~$ lsblk --tree -o PATH,MOUNTPOINT -J | jq -r '.blockdevices[] | del(select(.mountpoint!=null or .children[]?.mountpoint!=null)) | .path // empty' /dev/sr0
17. Display SCSI devices
To display SCSI devices only, use the '-S' or '--scsi' option.
$ lsblk -S
Sample output
jayce@Ubuntu-01:~$ lsblk -S NAME HCTL TYPE VENDOR MODEL REV SERIAL TRAN sda 32:0:0:0 disk VMware, VMware Virtual S 1.0 spi sr0 3:0:0:0 rom NECVMWar VMware Virtual SATA CDRW Drive 1.00 01000000000000000001 sata
Conclusion
Managing block storage devices is one of the tasks we will have to do often while working on Linux. The only way to become proficient at working with this command is practicing, so consider working with the examples we mentioned in this article.
