Exploring the 'lsscsi' Command for SCSI Devices (with examples)

The lsscsi command is a tool used in Linux to list SCSI devices and their attributes. It allows system administrators and users to easily obtain information about connected SCSI devices such as hard drives and other storage media, which can be critical for system management, troubleshooting, and understanding device configurations. Below, we explore several use cases of the lsscsi command, each highlighted with a motivation for usage, a breakdown of the command’s arguments, and a sample output for better understanding.

Use case 1: List All SCSI Devices

Code:

lsscsi

Motivation:

Listing all SCSI devices connected to your system is a fundamental task for understanding the storage configuration and ensuring all devices are properly recognized by the system. This is especially crucial in environments where storage configurations change frequently or when setting up new systems that incorporate SCSI devices.

Explanation:

The command lsscsi without any additional arguments will simply list all the SCSI devices attached to the system. This outputs a concise list, making it easy for users to quickly verify connected devices.

Example output:

[0:0:0:0]    disk    ATA      WDC WD10JPVX-75J 1A01  /dev/sda
[1:0:0:0]    cd/dvd  HL-DT-ST DVD+/-RW GU90N    A1C4  /dev/sr0

In this output, you can see identifiers for devices like disk drives and CD/DVD drives, alongside their respective types and device nodes.

Use case 2: List All SCSI Devices with Detailed Attributes

Code:

lsscsi -L

Motivation:

In situations where more detailed information about SCSI devices is necessary, using the -L option provides comprehensive details. This is particularly useful when diagnosing hardware issues, configuring system resources, or when needing to understand more about each connected device’s capabilities and settings.

Explanation:

The -L argument tells lsscsi to include additional attributes in the listing, such as device attributes and detailed information.

Example output:

[0:0:0:0]  disk  ATA      WDC WD10JPVX-75J  1A01  /dev/sda 
  dir: /dev 
  major: 8 
  minor: 0 
  ra: 128 
  prio: 1
[1:0:0:0]  cd/dvd HL-DT-ST DVD+/-RW GU90N   A1C4  /dev/sr0 
  dir: /dev 
  major: 11 
  minor: 0 
  ra: 128 
  prio: 2

This output lists in addition to the basic device information, valuable details such as major and minor numbers, the directory in which the device is mounted (/dev), and resource attributes, allowing deeper insight into the system’s SCSI device configuration.

Use case 3: List All SCSI Devices with Human-Readable Disk Capacity

Code:

lsscsi -s

Motivation:

Knowing the storage capacity of connected SCSI devices directly from the command line is incredibly valuable for system resource management. By using the -s option, users can easily make informed decisions regarding storage utilization and provisioning without needing to parse through additional command output manually.

Explanation:

The -s option appends storage capacity information to the SCSI device listing in a human-readable format, making it straightforward to ascertain how storage is distributed amongst devices.

Example output:

[0:0:0:0]  disk    ATA      WDC WD10JPVX-75J 1A01  /dev/sda   931GB  
[1:0:0:0]  cd/dvd  HL-DT-ST DVD+/-RW GU90N   A1C4  /dev/sr0   -

In this output for SCSI devices with the -s flag, each device is listed with its storage capacity. Note how the size is displayed, helping quickly identify capacities such as 931GB for the disk WDC WD10JPVX-75J.

Conclusion:

The lsscsi command is an essential tool in the toolbox of Linux system administrators and users who need to monitor, manage, and troubleshoot SCSI devices. By providing a variety of options to tailor output, lsscsi allows you to view basic device listings, detailed attributes, and storage capacities effortlessly, adapting to the specific information needs of the user or situation.