How to Expand LVM Disk for /docker-data

Taylor Walton

29-Jan-2026

How to Expand LVM Disk for /docker-data

This guide outlines the steps required to expand the logical volume and filesystem for /docker-data after additional disk capacity has been added to the underlying physical disk. This mount point is commonly used to store Docker data and persistent volumes.

Prerequisites

• The disk has already been expanded at the hypervisor or hardware level.
• The disk is used directly as an LVM physical volume (not partitioned).
• The mount point /docker-data is backed by an LVM logical volume.
• The filesystem is ext4 (most common for Docker data volumes).

Step-by-Step Instructions

1. Identify the Disk and Logical Volume
   First, determine which physical disk and logical volume back /docker-data:

   lsblk

   Example output:

   
   NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
   sdb 8:16 0 750G 0 disk
   └─vg_docker-lv_docker 254:1 0 500G 0 lvm /docker-data
    

   In this example:

   • /dev/sdb is the physical disk backing the volume group
   • /dev/mapper/vg_docker-lv_docker is the logical volume mounted at /docker-data
2. Resize the Physical Volume
   Make LVM aware of the newly available space on the expanded disk:

   pvresize /dev/sdb

3. Extend the Logical Volume
   Expand the logical volume to consume all remaining free space in the volume group:

   lvextend -l +100%FREE /dev/mapper/vg_docker-lv_docker

4. Resize the ext4 Filesystem
   Grow the ext4 filesystem to use the newly allocated space:

   resize2fs /dev/mapper/vg_docker-lv_docker

Verification

Confirm that the additional space is now available on /docker-data:

df -h /docker-data

Example Output

Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_docker-lv_docker 750G 420G 330G 56% /docker-data

Notes

• This procedure is safe to perform while Docker and containers are running.
• No service restart is required when expanding ext4 filesystems online.
• Always take a snapshot or backup before resizing storage on production systems.
• Monitor Docker volume growth to avoid excessive disk consumption.