How to use the command 'pvdisplay' (with examples)

The pvdisplay command is an essential tool for anyone working with Logical Volume Manager (LVM) on a Linux system. LVM provides a more flexible and convenient way to manage disk storage than traditional partitioning schemes. pvdisplay specifically focuses on physical volumes, which are the building blocks for LVM, providing storage devices that can be grouped into volume groups and then subdivided into logical volumes. Using pvdisplay, users can inspect and verify the status of physical volumes, ensuring that they are correctly configured and functioning within the LVM framework.

Use case 1: Display information about all physical volumes

Code:

sudo pvdisplay

Motivation for using this example:

When managing LVM setups, particularly on systems with multiple storage devices, it’s crucial to have a clear overview of all physical volumes. By displaying comprehensive information about each physical volume, administrators can ensure that all volumes are active, healthy, and properly integrated into the system’s storage architecture. This information is vital for routine maintenance, troubleshooting, and during any expansion or reconfiguration of the storage system.

Explanation of the command:

• sudo: This command is run with superuser privileges because accessing LVM information requires administrative rights. Without superuser privileges, the information might be incomplete or inaccessible.
• pvdisplay: This is the main command used to display detailed information about all physical volumes present on the system. It provides attributes like the size, volume group association, UUID, and any other pertinent data related to physical volumes.

Example output:

  --- Physical volume ---
  PV Name               /dev/sda1
  VG Name               vg_data
  PV Size               200.00 GiB / not usable 3.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              51199
  Free PE               0
  Allocated PE          51199
  PV UUID               abcd-1234-efgh-5678-ijkl
                       
  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               vg_backup
  PV Size               500.00 GiB / not usable 4.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              127999
  Free PE               32000
  Allocated PE          95999
  PV UUID               mnop-1234-qrst-5678-uvwx

Use case 2: Display information about the physical volume on drive /dev/sdXY

Code:

sudo pvdisplay /dev/sdXY

Motivation for using this example:

In some scenarios, administrators may want to inspect a specific physical volume, especially when diagnosing issues, performing targeted maintenance, or verifying the configuration of newly added storage devices. By specifying a particular volume, users can focus on the details of interest without sifting through potentially overwhelming data for all volumes. This targeted approach allows for efficient troubleshooting and precise management of individual physical components within the system.

Explanation of the command:

• sudo: Given the nature of the task, root privileges are necessary to access and inspect storage on a granular level securely.
• pvdisplay: The base command used to fetch details of LVM physical volumes.
• /dev/sdXY: This argument specifies the exact physical volume to examine. The /dev/sdXY format is a typical Linux convention where sdX denotes the drive identifier, and Y is the partition number. Users replace /dev/sdXY with the exact path of the physical volume they intend to investigate.

Example output:

  --- Physical volume ---
  PV Name               /dev/sda1
  VG Name               vg_data
  PV Size               200.00 GiB / not usable 3.00 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              51199
  Free PE               0
  Allocated PE          51199
  PV UUID               abcd-1234-efgh-5678-ijkl

Conclusion:

The pvdisplay command is a vital utility for system administrators working with LVM. Whether you need an overview of all physical volumes or details on a specific one, pvdisplay provides the necessary information for managing and maintaining disk storage effectively. With its option for broad or targeted display of physical volume data, it supports a wide range of administrative tasks, from daily maintenance to troubleshooting and beyond. Understanding and utilizing the pvdisplay command ensures that your LVM setup remains robust, adaptable, and well-documented.