Resize partitions and file systems of Linux system disks - Best Practices| Alibaba Cloud Documentation Center

This topic describes how to use growpart and resize2fs to resize the partitions and file systems of Linux system disks.

Prerequisites

Before you resize the partitions and file systems of a system disk, make sure that the following requirements are met:

A snapshot is created to back up data.
To prevent data loss caused by accidental changes, we recommend that you create a snapshot to back up your data. For more information, see Create a snapshot for a disk.
A data disk is resized in the console.
If no data disks are resized, see Step 2: Resize the disk in the ECS console to resize a data disk.
Connect to an ECS instance.
For more information about connection methods, see Connection methods.
The growpart or xfsprogs tool is installed based on your operating system.
- Alibaba Cloud Linux 2 and CentOS 7
  Run the yum install <Package name> command. Example:
```
yum install cloud-utils-growpart xfsprogs -y
```
- Ubuntu 14, Ubuntu 16, Ubuntu 18, and Debian 9
  Run the apt install <Package name> command. Example:
```
apt install cloud-guest-utils xfsprogs -y
```
- Debian 8, openSUSE 42.3, openSUSE 13.1, and SUSE Linux Enterprise Server 12 SP2
  Use the upstream version of growpart or xfsprogs.
Note If the partitions or file systems cannot be resized due to issues with growpart or xfsprogs, we recommend that you re-install the tool.
The uname -a command is run to check the kernel version of the instance operating system.
- If the kernel version of your instance operating system is 3.6.0 or later, see the Procedure for instances with kernels 3.6.0 or later section of this topic.
- If the kernel version of your instance operating system such as CentOS 6, Debian 7, or SUSE Linux Enterprise Server 11 SP4 is earlier than 3.6.0, you must restart the instance by using the Elastic Compute Service (ECS) console or by calling an API operation to resize the partitions or file systems. For more information, see the Procedure for instances with kernels earlier than 3.6.0 section of this topic.

Background information

The procedures in this topic apply to disks that have the following partition formats and file system types:

Partition formats: master boot record (MBR) and GUID Partition Table (GPT)
File system types: ext, xfs, and btrfs

Procedure for instances with kernels 3.6.0 or later

In this example, Alibaba Cloud Linux 2.1903 LTS 64-bit is used to describe how to resize the partitions and file systems of the system disk.

Note The commands in the example also apply to CentOS 7.

Run the following command to check the size of the system disk:

fdisk -l

In the following example command output, the size of the /dev/vda disk is 100 GiB:

[root@ecshost ~]# 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: 0x000bad2b

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    83886046    41941999   83  Linux

Run the following command to check the sizes of the partitions and the types of the file systems:

df -Th

In the following example command output, the size of the /dev/vda1 partition is 40 GiB, and the file system type is ext4:

[root@ecshost ~]# df -Th
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  869M     0  869M   0% /dev
tmpfs          tmpfs     879M     0  879M   0% /dev/shm
tmpfs          tmpfs     879M  460K  878M   1% /run
tmpfs          tmpfs     879M     0  879M   0% /sys/fs/cgroup
/dev/vda1      ext4       40G  1.8G   36G   5% /
tmpfs          tmpfs     176M     0  176M   0% /run/user/0

Run the following command to resize a partition:
```
growpart <DeviceName> <PartionNumber>
```
In the following example command output, the first partition /dev/vda1 of the system disk is resized:
```
[root@ecshost ~]# growpart /dev/vda 1
CHANGED: partition=1 start=2048 old: size=83883999 end=83886047 new: size=209713119 end=209715167
```
Note If the unexpected output in sfdisk --version [sfdisk, from util-linux 2.23.2] error appears when you run the growpart /dev/vda 1 command, change the character encoding type to resolve the issue. For more information, see FAQ.

Resize the file system.

Run the df -Th command to check the file system type. Then, use one of the following methods to resize the file system based on the file system type:

If the file system type is ext such as ext3 and ext4, run the following command to resize the file system:

resize2fs <PartitionName>

In the following example command output, the file system of the /dev/vda1 partition is resized:

[root@ecshost ~]# resize2fs /dev/vda1
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 7
The filesystem on /dev/vda1 is now 26214139 blocks long.

If the file system type is xfs, run the following command to resize the file system:

xfs_growfs <mountpoint>

In the following example command output, the file system of the /dev/vda1 partition is resized. The mount point of the /dev/vda1 partition is the / root directory.

[root@ecshost ~]# xfs_growfs /
meta-data=/dev/vda1              isize=512    agcount=13, agsize=1310656 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=15728379, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 15728379 to 20971259

Note The command to run may vary based on the version of xfs_growfs. You can run the xfs_growfs --help command to check the corresponding command to run.

If the file system type is btrfs, run the following command to resize the file system:
```
btrfs filesystem resize max <mountpoint>
```
In the following example command output, the file system of the /dev/vda1 partition is resized. The mount point of the /dev/vda1 partition is the / root directory.
```
[root@ecshost ~]# btrfs filesystem resize max /
```

Run the following command to view the results of disk resizing:

df -h

In the following example command output, the size of the /dev/vda1 partition is 100 GiB, which indicates that the partition is resized.

[root@ecshost ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        869M     0  869M   0% /dev
tmpfs           879M     0  879M   0% /dev/shm
tmpfs           879M  492K  878M   1% /run
tmpfs           879M     0  879M   0% /sys/fs/cgroup
/dev/vda1        99G  1.8G   93G   2% /
tmpfs           176M     0  176M   0% /run/user/0

Procedure for instances with kernels earlier than 3.6.0

In this example, CentOS 6 is used to describe how to resize the partitions and file systems of the system disk.

Change the source address of a YUM repository on CentOS 6.
CentOS 6 has reached its end of life (EOL). To install the software package on CentOS 6 by using YUM, you must change the source address of the YUM repository. For more information, see Change the CentOS 6 source address.
Run the following command to install dracut-modules-growroot:
```
yum install -y dracut-modules-growroot
```
Note If a package manager other than YUM is used, change yum in the preceding command based on the package manager.
Run the following command to overwrite the existing initramfs file:
```
dracut -f
```

Check the size of the system disk and the partitions and file systems.

Run the following command to check the size of the system disk:

fdisk -l

In the following example command output, the size of the /dev/vda disk is 100 GiB:

[root@ecshost ~]# 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

Run the following command to check the partitions of the system disk and the types of the file systems:
```
df -Th
```
In the following example command output, the size of the /dev/vda1 partition is 20 GiB, and the file system type is ext4:
```
[root@ecshost ~]# df -h
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      ext4       20G  1.1G   18G   6% /
tmpfs          tmpfs     7.8G     0  7.8G   0% /dev/shm
```

Run the following command to resize a partition:

growpart <DeviceName> <PartionNumber>

In the following example command output, the first partition /dev/vda1 of the system disk is resized:

[root@ecshost ~]# growpart /dev/vda 1
CHANGED: partition=1 start=2048 old: size=41940992 end=41943040 new: size=209710462,end=209712510

Restart the instance in the ECS console.

Notice The resize operation does not take effect until you restart the instance by using the ECS console or by calling the RebootInstance operation. For more information, see Restart an instance and RebootInstance.
Connect to the instance.
Resize the file system.
Run the df -h command to check the file system type. Then, use one of the following methods to resize the file system based on the file system type:
- If the file system type is ext such as ext3 and ext4, run the following command to resize the file system:
```
resize2fs <PartitionName>
```
  In the following example command output, the file system of the /dev/vda1 partition is resized:
  [root@ecshost ~]# 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.
- If the file system type is xfs, run the following command to resize the file system:
```
xfs_growfs <mountpoint>
```
  In the following example command output, the file system of the /dev/vda1 partition is resized. The mount point of the /dev/vda1 partition is the / root directory.
```
[root@ecshost ~]# xfs_growfs /
```
  Note The command to run may vary based on the version of xfs_growfs. Run the xfs_growfs --help command to check the corresponding command to run.
Run the following command to check the sizes of the disk partitions:
```
df -h
```
In the following example command output, the size of the /dev/vda1 partition is 100 GiB, which indicates that the partition is resized.
```
[root@ecshost ~]# 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
```