10+ lvchange command examples in Linux [Cheat Sheet]

Introduction to lvchange command

lvchange is one of the command-line tools to configure and manage the logical volume in the Linux system. lvchange command allows you to change attributes of a logical volume in the volume group. You can perform different operations such as activate/deactivate, change access permission and set/reset contiguous allocation policy on the logical volume.

 

Are you new to LVM and still learning how it works?

We have written detailed articles covering different areas of managing logical volumes, which you can follow using the below links:

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Manage Logical Volume in Linux - One STOP Solution
Understand LVM Architecture
Create LVM during installation RHEL/CentOS 7/8
How to use LVM Snapshot for Backup and Restore
Create Mirrored Logical Volume
Create Striped Logical Volume

 

Syntax to use lvchange command

lvchange command is available in the lvm2 package in Linux. You will need the root privileges to run the lvchange command.

The syntax for lvchange command is:

$ sudo lvchange option LV

 

Different examples to use lvchange command

1. Deactivate or Activate any logical volume

One of the important functions of lvchange command is to control the availability of the logical volumes for use. You can activate or deactivate a logical volume with the -a option of the lvchange command. By default, when you create a logical volume it is activated.

The following command deactivates the logical volume lvol1 in the volume group vol_grp.

$ sudo lvchange -an vol_grp/lvol1

Sample Output:

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The a attribute represents the active logical volume.

lvchange command to deactivate the logical volume

The -ay option activates the logical volume in the volume group.

$ sudo lvchange -ay vol_grp/lvol1

Sample Output:

lvchange command to activate the logical volume

 

2. Set or reset the contiguous allocation policy for logical volumes

The -C option with y argument sets the contiguous allocation policy for the logical volume.

$ sudo lvchange -Cy vol_grp/lv_one

Sample Output:

lvchange command to set contiguous allocation policy

The -C option with n argument resets the contiguous allocation policy for the logical volume.

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$ sudo lvchange -Cn vol_grp/lv_one

Sample Output:

lvchange command to reset contiguous allocation policy

NOTE:

It is only possible to change a non-contiguous allocation policy to contiguous if all of the allocated physical extents in the logical volume are already contiguous.

 

3. Change access permission of logical volume to read-only

The -p or --permission option changes access permission to read-only or read/write. You can use r flag for the read-only permission.

For example, the following command changes the permission of the logical volume lvol1 in the volume group vol_grp to be read-only.

$ sudo lvchange -pr vg00/lvol1

OR

$ sudo lvchange --permission r vg00/lvol1

Sample Output:

lvchange command to change permission to read only of logical volume

 

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4. Change access permission of logical volume to read/write

The rw flag with -p or --permisssion option changes the access permission of the logical volume to read/write.

$ sudo lvchange -prw vol_grp/lvol1

OR

$ sudo lvchange --permission rw vol_grp/lvol1

Sample Output:

lvchange command to change permission to read write on the logical volume

 

5. Make the minor number specified persistent for logical volume

The -M or --persistent option with y flag makes the minor device number persistent for the logical volume.

$ sudo lvchange -M y --minor NUM vol_grp/lvol0

OR

$ sudo lvchange --persistent y --minor NUM vol_grp/lvol0

Sample Output:

lvchange command to make the minor device number persistent for the logical volume

 

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6. Start or stop monitoring of a logical volume

The --monitor option is used to start or stop monitoring a mirrored or snapshot logical volume from dmeventd if it is installed.

To start monitoring, use y flag:

$ sudo lvchange --monitor y vol_grp/lvol1

To stop monitoring, use n flag:

$ sudo lvchange --monitor n vol_grp/lvol1

 

7. Resynchronize a mirror or raid logical volume

The --resync of lvchange command forces the complete resynchronization of a mirrored or raid logical volume. Normally, it is not required as synchronization happens automatically.

$ sudo lvchange --resync vol_grp/lvol_mirror

 

8. Resynchronize or check a raid logical volume

The --syncaction option initiates different types of RAID synchronization. It reads all data and parity blocks in the array and checks for discrepancies (mismatches between mirrors or incorrect parity values).

check flag counts discrepancies.

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$ sudo lvchange --syncaction check vol_grp/lvol_raid

repair flag corrects discrepancies.

$ sudo lvchange --syncaction repair vol_grp/lvol_raid

 

9. Reconstruct data on specific PVs of a raid logical volume

The --rebuild option selects a physical volume to rebuild in a raid logical volume. You can use this option instead of --resync or --syncaction repair when the PVs with corrupted data are known. It is because their data should be reconstructed rather than reconstructing default (rotating) data.

$ sudo lvchange --rebuild vol_grp/lvol_raid

 

10. Poll a logical volume to restart its incomplete process

Without polling, the backgrounded transformation process of a logical volume will never be complete. For example, if there is an incomplete transformation, e.g. pvmove or lvconvert interrupted by reboot or crash, you can use --poll y to restart the process from its last checkpoint.

$ sudo lvchange --poll y vol_grp/lvol0
NOTE:

It is not appropriate to immediately poll a logical volume when it is activated, you should use --poll n to defer polling and then --poll y to restart the process.

 

11. Reactivate a logical volume using the latest metadata

If the logical volume is active, you can use the --refresh option to reload its metadata. It is useful when something has gone wrong or you're doing clustering manually without a clustered lock manager.

$ sudo lvchange --refresh vol_grp/lvol1

 

12. Set zeroing mode for thin pool logical volume

The -Z or --zero option sets or resets zeroing mode for thin pool logical volume.

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$ sudo lvchange -Z n vol_grp/thinpool_lv

OR

$ sudo lvchange --zero n vol_grp/thinpool_lv

Sample Output:

golinux@ubuntu-PC:~$ sudo lvchange -Z n vol_grp/thinpool_lv
  Logical volume vol_grp/thinpool_lv changed.
NOTE:

Already provisioned blocks from thin pool LV in non-zero mode are not cleared in unwritten parts when setting zero to y.

 

Conclusion

This article teaches you to use lvchange command to change the attributes of a logical volume. We hope this article was helpful for you to understand lvchange command in Linux. If you have any queries, please share them in the comment section below.

 

What’s Next

10+ lvcreate command examples in Linux [Cheat Sheet]
vgcreate command examples in Linux [Cheat Sheet]

 

Further Reading

man page for lvchange command

 

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