This topic describes how to use the growpart and resize2fs tools to resize the system disk and extend the file system of a Linux instance.

Overview

This topic uses the /dev/vda1 partition of the /dev/vda system disk as an example.

  • You can resize the disk only if a combination of the following conditions are met. For more information, see Resize the system disk online.
    • Partition format: mbr and gpt
    • File system: ext, XFS, Btrfs, and UFS
    • Operating system: The kernel version is V3.6.0 or later (run the uname -a command to check the version).
  • If the operating system is earlier than V3.6.0 (for example CentOS 6, Debian 7, and SUSE Linux Enterprise Server 11 SP4), you must restart the operating system before you can resize the system disk. For more information, see Resize the system disk offline.

Preparations

  1. Resize the disk by using the ECS console or calling the API.
  2. Create a snapshot to back up data.
  3. Mount the disk to an ECS instance that is in the Running state. For information on how to connect to an ECS instance, see Overview.
  4. Install the required growpart tool according to your operating system.
    Table 1. Install the growpart tool in different operating systems
    Operating system Growpart tool
    CentOS 7 
    yum install cloud-utils-growpart
    Aliyun Linux
    Ubuntu 14 
    apt install cloud-guest-utils
    Ubuntu 16
    Ubuntu 18
    Debian 9
    Debian 8 Use the upstream growpart tool.
    OpenSUSE 42.3
    OpenSUSE 13.1
    SUSE Linux Enterprise Server 12 SP2

Resize the system disk online

This procedure uses a CentOS 7 instance as an example to describe how to resize a partition online.

  1. Install the required growpart tool according to your operating system. 
    [root@localhost ~]# yum install -y cloud-utils-growpart
  2. Run the fdisk -l command to view the current disk size. In this example, the disk size (/dev/vda) is 100 GiB. 
    [root@localhost ~]# fdisk -l

Disk /dev/vda: 107.4 GB, 107374182400 bytes, 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0008d73a

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    41943039    20970496   83  Linux
  3. Run the df -h command to view the disk partition size. In this example, the disk partition size (/dev/vda1) is 20 GiB. 
    [root@localhost ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        20G  1.5G   18G   8% /
devtmpfs        7.8G     0  7.8G   0% /dev
tmpfs           7.8G  344K  7.8G   1% /run
tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup
tmpfs           1.6G     0  1.6G   0% /run/user/0
  4. Run the growpart <DeviceName><PartionNumber> command to call the growpart tool to resize the target system disk and partition. In this example, the first partition of the system disk is resized. 
    [root@localhost ~]# growpart /dev/vda 1
CHANGED: partition=1 start=2048 old: size=41940992 end=41943040 new: size=209710462,end=209712510
  5. Run the resize2fs <PartitionName> command to call the resize2fs tool to extend the file system. In this example, the file system of the /dev/vda1 partition in the system disk is extended. 
    [root@localhost ~]# resize2fs /dev/vda1
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 7
The filesystem on /dev/vda1 is now 26213807 blocks long.
  6. Run the df -h command to view the size of the disk partition. In this example, the returned partition size (/dev/vda1) is 100 GiB, which means that the partition is extended. 
    [root@localhost ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        99G  1.6G   93G   2% /
devtmpfs        7.8G     0  7.8G   0% /dev
tmpfs           7.8G     0  7.8G   0% /dev/shm
tmpfs           7.8G  500K  7.8G   1% /run
tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup
tmpfs           1.6G     0  1.6G   0% /run/user/0

Resize the system disk offline

This procedure uses a CentOS 6 instance as an example to describe how to resize a partition offline.

  1. Install the required growpart and dracut-modules-growroot tools according to your operating system. 
    [root@AliYunOS ~]# yum install -y cloud-utils-growpart dracut-modules-growroot
[root@AliYunOS ~]# dracut -f
  2. Run the fdisk -l command to view the current disk size. In this example, the disk size (/dev/vda) is 100 GiB. 
    [root@AliYunOS ~]# fdisk -l

Disk /dev/vda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0003a7b4

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1        2611    20970496   83  Linux
  3. Run the df -h command to view the disk partition size. In this example, the disk partition size (/dev/vda1) is 20 GiB. 
    [root@AliYunOS ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        20G  1.1G   18G   6% /
tmpfs           7.8G     0  7.8G   0% /dev/shm
  4. Run the growpart <DeviceName><PartionNumber> command to call the growpart tool to resize the target system disk and partition. In this example, the first partition of the system disk is resized. 
    [root@AliYunOS ~]# growpart /dev/vda 1
CHANGED: partition=1 start=2048 old: size=41940992 end=41943040 new: size=209710462,end=209712510
  5. Restart the instance. 
    [root@AliYunOS ~]# reboot
  6. Connect to the instance again.
  7. Run the resize2fs <PartitionName> command to call the resize2fs tool to extend the file system. In this example, the file system of the /dev/vda1 partition in the system disk is extended. 
    [root@AliYunOS ~]# resize2fs /dev/vda1
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 7
Performing an on-line resize of /dev/vda1 to 26213807 (4k) blocks.
The filesystem on /dev/vda1 is now 26213807 blocks long.
  8. Run the df -h command to view the size of the disk partition. In this example, the returned partition size (/dev/vda1) is 100 GiB, which means that the partition is extended. 
    [root@AliYunOS ~]# fdisk -l

Disk /dev/vda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0003a7b4

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1       13054   104855231   83  Linux
[root@AliYunOS ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        99G  1.1G   93G   2% /
tmpfs           7.8G     0  7.8G   0% /dev/shm