Help Center/ Elastic Volume Service/ Best Practices/ Extending Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)/ Extending Data Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)

Updated on 2023-06-21 GMT+08:00

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Extending Data Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)

Scenarios

After a disk has been expanded on the management console, the disk size is enlarged, but the additional space cannot be used directly.

In Linux, you must allocate the additional space to an existing partition or a new partition.

This section uses CentOS 7.4 64bit as the sample OS to describe how to extend an MBR or GPT partition. The way you allocate additional space depends on the OS. This example is used for reference only. For detailed operations and differences, see the corresponding OS documentations.

Creating a New MBR Partition
Extending an Existing MBR Partition
Creating a New GPT Partition
Extending an Existing GPT Partition

Exercise caution when expanding the disk capacity. Incorrect operations may lead to data loss or exceptions. So you are advised to back up the disk data using backups or snapshots before expansion. For details about backups, see Managing EVS Backups. For details about snapshots, see Creating a Snapshot (OBT).
If the OS kernel version is earlier than 3.6.0, the extension of an existing MBR partition and file system takes effect only after a system reboot, and services will be interrupted. After you run reboot, the additional space is automatically added to the partition at the end of the system disk.
If you do not want to reboot your ECS, you can migrate data from the system disk to a data disk on the same ECS, detach the data disk, and attach it to an ECS whose OS kernel version is later than 3.6.0. In this case, the disk partition and file system can be extended without a reboot. You can then detach and attach back the extended disk to the original ECS, and migrate data back to the system disk. There are risks in migrating data. Back up the data before migration. To extend partitions and file systems on an ECSwhose kernel version is greater than 3.6.0, see Expanding Disk Partitions and File Systems (Linux).

Prerequisites

You have expanded the system disk capacity and attached the system disk to a server on the management console. For details, see Expanding Capacity for an In-use EVS Disk or Expanding Capacity for an Available EVS Disk.
You have logged in to the server.
- For how to log in to an ECS, see Logging In to an ECS.
- For how to log in to a BMS, see Logging In to the BMS.

Creating a New MBR Partition

Originally, data disk /dev/vdb has 100 GB and one partition (/dev/vdb1), and then 50 GB is added to the disk. The following procedure shows you how to create a new MBR partition /dev/vdb2 with this 50 GB.

Run the following command to view the disk partition information:

fdisk -l

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# fdisk -l

Disk /dev/vda: 42.9 GB, 42949672960 bytes, 83886080 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: 0x000bcb4e

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    83886079    41942016   83  Linux

Disk /dev/vdb: 161.1 GB, 161061273600 bytes, 314572800 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: 0x38717fc1

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048   209715199   104856576   83  Linux

Run the following command to enter fdisk:

fdisk Disk

In this example, run the following command:

fdisk /dev/vdb

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help):

Enter n and press Enter to create a new partition.
Information similar to the following is displayed:
```
Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p):
```
There are two types of disk partitions:
- Choosing p creates a primary partition.
- Choosing e creates an extended partition.
If the MBR partition style is used, a maximum of 4 primary partitions, or 3 primary partitions and 1 extended partition can be created. The extended partition cannot be used directly and must be divided into logical partitions before use.

Disk partitions created using GPT are not categorized.
In this example, a primary partition is created. Therefore, enter p and press Enter to create a primary partition.
Information similar to the following is displayed:
```
Select (default p): p
Partition number (2-4, default 2):
```
Partition number indicates the serial number of the primary partition. Because partition number 1 has been used, the value ranges from 2 to 4.
Enter the serial number of the primary partition and press Enter. Partition number 2 is used in this example. Therefore, enter 2 and press Enter.
Information similar to the following is displayed:
```
Partition number (2-4, default 2): 2
First sector (209715200-314572799, default 209715200):
```
First sector indicates the start sector. The value ranges from 209715200 to 314572799, and the default value is 209715200.
Enter the new partition's start sector and press Enter. In this example, the default start sector is used.

The system displays the start and end sectors of the partition's available space. You can customize the value within this range or use the default value. The start sector must be smaller than the partition's end sector.
Information similar to the following is displayed:
```
First sector (209715200-314572799, default 209715200):
Using default value 209715200
Last sector, +sectors or +size{K,M,G} (209715200-314572799, default 314572799):
```
Last sector indicates the end sector. The value ranges from 209715200 to 314572799, and the default value is 314572799.
Enter the new partition's end sector and press Enter. In this example, the default end sector is used.

The system displays the start and end sectors of the partition's available space. You can customize the value within this range or use the default value. The start sector must be smaller than the partition's end sector.
Information similar to the following is displayed:
```
Last sector, +sectors or +size{K,M,G} (209715200-314572799, default 314572799):
Using default value 314572799
Partition 2 of type Linux and of size 50 GiB is set

Command (m for help): 
```

Enter p and press Enter to view the new partition.

Information similar to the following is displayed:

Command (m for help): p

Disk /dev/vdb: 161.1 GB, 161061273600 bytes, 314572800 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: 0x38717fc1

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048   209715199   104856576   83  Linux
/dev/vdb2       209715200   314572799    52428800   83  Linux

Command (m for help):

Enter w and press Enter to write the changes to the partition table.

Information similar to the following is displayed:

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

In case that you want to discard the changes made before, you can exit fdisk by entering q.

Run the following command to synchronize the new partition table to the OS:

partprobe

Run the following command to set the file system format for the new partition:

mkfs -t File system Disk partition

Sample command of the ext* file system:

mkfs -t ext4 /dev/vdb2

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# mkfs -t ext4 /dev/vdb2
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
3276800 inodes, 13107200 blocks
655360 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2162163712
400 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

Sample command of the xfs file system:

mkfs -t xfs /dev/vdb2

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# mkfs -t xfs /dev/vdb2 
meta-data=/dev/vdb2              isize=512     agcount=4, agsize=3276800 blks
         =                       sectsz=512    attr=2, projid32bit=1
         =                       crc=1         finobt=0, sparse=0
data     =                       bsize=4096    blocks=13107200, imaxpct=25
         =                       sunit=0       swidth=0 blks
naming   =version2               bsize=4096    ascii-ci=0 ftype=1
log      =internal log           bsize=4096    blocks=6400, version=2
         =                       sectsz=512    sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096    blocks=0, rtextents=0

The formatting takes a while, and you need to observe the system running status. Once done is displayed in the command output, the formatting is complete.

(Optional) Run the following command to create a mount point:

Perform this step if you want to mount the partition on a new mount point.

mkdir Mount point

In this example, run the following command to create the /mnt/test mount point:

mkdir /mnt/test
Run the following command to mount the new partition:

mount Disk partition Mount point

In this example, run the following command to mount the new partition /dev/vdb2 on /mnt/test:

mount /dev/vdb2 /mnt/test

If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.

Run the following command to view the mount result:

df -TH

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# df -TH
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      ext4       43G  1.9G   39G   5% /
devtmpfs       devtmpfs  2.0G     0  2.0G   0% /dev
tmpfs          tmpfs     2.0G     0  2.0G   0% /dev/shm
tmpfs          tmpfs     2.0G  9.1M  2.0G   1% /run
tmpfs          tmpfs     2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs          tmpfs     398M     0  398M   0% /run/user/0
/dev/vdb1      ext4      106G   63M  101G   1% /mnt/sdc
/dev/vdb2      ext4       53G   55M   50G   1% /mnt/test

If the server is restarted, the mounting will become invalid. You can set automatic mounting for partitions at system start by modifying the /etc/fstab file. For details, see Setting Automatic Mounting at System Start.

Extending an Existing MBR Partition

If the additional space is allocated to an existing partition, data on the disk will not be cleared but you must use umount to unmount the existing partition. In this case, services will be affected.

Originally, data disk /dev/vdb has 150 GB and two partitions (/dev/vdb1 and /dev/vdb2, and then 80 GB is added to the disk. The following procedure shows you how to add this 80 GB to the existing MBR partition /dev/vdb2.

During an expansion, the additional space is added to the end of the disk. Therefore, if the disk has multiple partitions, the additional space can only be allocated to the partition at the disk end.

Run the following command to view the disk partition information:

fdisk -l

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# fdisk -l

Disk /dev/vda: 42.9 GB, 42949672960 bytes, 83886080 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: 0x000bcb4e

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    83886079    41942016   83  Linux

Disk /dev/vdb: 247.0 GB, 246960619520 bytes, 482344960 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: 0x38717fc1

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048   209715199   104856576   83  Linux
/dev/vdb2       209715200   314572799    52428800   83  Linux

In the command output, take note of the partition's start and end sectors. In this example, /dev/vdb2's start sector is 209715200, and its end sector is 314572799.

View the /dev/vdb capacity and check whether the additional space is included.

If the additional space is not included, refresh the capacity according to Extending SCSI Data Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0).
If the additional space is included, take note of the start and end sectors of the target partition and then go to 2. These values will be used in the subsequent operations.

Run the following command to unmount the partition:

umount Disk partition

In this example, run the following command:

umount /dev/vdb2

Run the following command to enter fdisk:

fdisk Disk

In this example, run the following command:

fdisk /dev/vdb

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help):

Run the following command to delete the partition to be extended:
1. Enter d and press Enter to delete the partition.
  Information similar to the following is displayed:
```
Command (m for help): d
Partition number (1,2, default 2):
```
2. Enter the partition number and press Enter to delete the partition. In this example, enter 2.
  Information similar to the following is displayed:
```
Partition number (1,2, default 2): 2
Partition 2 is deleted

Command (m for help): 
```
  After deleting the partition, recreate the partition according to the following steps, and data on this disk will not be lost.
Enter n and press Enter to create a new partition.
Information similar to the following is displayed:
```
Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p):
```
There are two types of disk partitions:
- Choosing p creates a primary partition.
- Choosing e creates an extended partition.
If the MBR partition style is used, a maximum of 4 primary partitions, or 3 primary partitions and 1 extended partition can be created. The extended partition cannot be used directly and must be divided into logical partitions before use.

Disk partitions created using GPT are not categorized.
Ensure that the entered partition type is the same as the partition had before. In this example, a primary partition is used. Therefore, enter p and press Enter to create a primary partition.
Information similar to the following is displayed:
```
Select (default p): p
Partition number (2-4, default 2): 
```
Partition number indicates the serial number of the primary partition.
Ensure that entered partition number is the same as the partition had before. In this example, partition number 2 is used. Therefore, enter 2 and press Enter.
Information similar to the following is displayed:
```
Partition number (2-4, default 2): 2
First sector (209715200-482344959, default 209715200):
```
In the command output, First sector specifies the start sector.
Data will be lost if the following operations are performed:
- Select a start sector other than the partition had before.
- Select an end sector smaller than the partition had before.
Ensure that the entered start sector is the same as the partition had before. In this example, start sector 209715200 is recorded in 1. Therefore, enter 209715200 and press Enter.
Information similar to the following is displayed:
```
First sector (209715200-482344959, default 209715200):
Using default value 209715200
Last sector, +sectors or +size{K,M,G} (209715200-482344959, default 482344959):
```
In the command output, Last sector specifies the end sector.
Ensure that the entered end sector is larger than or equal to the end sector recorded in 1. In this example, the recorded end sector is 314572799, and the default end sector is used. Therefore, enter 482344959 and press Enter.
Information similar to the following is displayed:
```
Using default value 209715200
Last sector, +sectors or +size{K,M,G} (209715200-482344959, default 482344959):
Using default value 482344959
Partition 2 of type Linux and of size 130 GiB is set

Command (m for help): 
```
The partition is created.

Enter p and press Enter to view the partition details.

Information similar to the following is displayed:

Command (m for help): p

Disk /dev/vdb: 247.0 GB, 246960619520 bytes, 482344960 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: 0x38717fc1

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048   209715199   104856576   83  Linux
/dev/vdb2       209715200   482344959   136314880   83  Linux

Command (m for help):

Enter w and press Enter to write the changes to the partition table.

Information similar to the following is displayed:

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

In case that you want to discard the changes made before, you can exit fdisk by entering q.

Run the following command to synchronize the new partition table to the OS:

partprobe
Perform the following operations based on the file system of the disk:
- For the ext* file system
  1. Run the following command to check the correctness of the file system on the partition:
    e2fsck -f Disk partition
    
    In this example, run the following command:
    
    e2fsck -f /dev/vdb2
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# e2fsck -f /dev/vdb2
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vdb2: 11/3276800 files (0.0% non-contiguous), 251790/13107200 blocks
```
  2. Run the following command to extend the file system of the partition:
    resize2fs Disk partition
    
    In this example, run the following command:
    
    resize2fs /dev/vdb2
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# resize2fs /dev/vdb2
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vdb2 to 34078720 (4k) blocks.
The filesystem on /dev/vdb2 is now 34078720 blocks long.
```
  3. (Optional) Run the following command to create a mount point:
    Perform this step if you want to mount the partition on a new mount point.
    
    mkdir Mount point
    
    In this example, run the following command to create the /mnt/test mount point:
    
    mkdir /mnt/test
  4. Run the following command to mount the partition:
    mount Disk partition Mount point
    
    In this example, run the following command to mount the partition /dev/vdb2 on /mnt/test:
    
    mount /dev/vdb2 /mnt/test
    
    If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.
- For the xfs file system
  1. (Optional) Run the following command to create a mount point:
    Perform this step if you want to mount the partition on a new mount point.
    
    mkdir Mount point
    
    In this example, run the following command to create the /mnt/test mount point:
    
    mkdir /mnt/test
  2. Run the following command to mount the partition:
    mount Disk partition Mount point
    
    In this example, run the following command to mount the partition /dev/vdb2 on /mnt/test:
    
    mount /dev/vdb2 /mnt/test
    
    If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.
  3. Run the following command to extend the file system of the partition:
    sudo xfs_growfs Disk partition
    
    In this example, run the following command:
    
    sudo xfs_growfs /dev/vdb2
    
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# sudo xfs_growfs /dev/vdb2 
meta-data=/dev/vdb2              isize=512     agcount=4, agsize=3276800 blks
         =                       sectsz=512    attr=2, projid32bit=1
         =                       crc=1         finobt=0, spinodes=0
data     =                       bsize=4096    blocks=13107200, imaxpct=25
         =                       sunit=0       swidth=0 blks
naming   =version2               bsize=4096    ascii-ci=0 ftype=1
log      =internal               bsize=4096    blocks=6400, version=2
         =                       sectsz=512    sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096    blocks=0, rtextents=0
data blocks changed from 13107200 to 34078720.
```

Run the following command to view the mount result:

df -TH

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# df -TH
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      ext4       43G  1.9G   39G   5% /
devtmpfs       devtmpfs  2.0G     0  2.0G   0% /dev
tmpfs          tmpfs     2.0G     0  2.0G   0% /dev/shm
tmpfs          tmpfs     2.0G  9.1M  2.0G   1% /run
tmpfs          tmpfs     2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs          tmpfs     398M     0  398M   0% /run/user/0
/dev/vdb1      ext4      106G   63M  101G   1% /mnt/sdc
/dev/vdb2      ext4      138G   63M  131G   1% /mnt/test

Creating a New GPT Partition

Originally, data disk /dev/vdb has 100 GB and one partition (/dev/vdb1), and then 50 GB is added to the disk. The following procedure shows you how to create a new GPT partition /dev/vdb2 with this 50 GB.

Run the following command to view the disk partition information:

lsblk

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    253:0    0   40G  0 disk
└─vda1 253:1    0   40G  0 part /
vdb    253:16   0  150G  0 disk
└─vdb1 253:17   0  100G  0 part /mnt/sdc

Run the following command to enter parted:

parted Disk

In this example, run the following command:

parted /dev/vdb
Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# parted /dev/vdb
GNU Parted 3.1
Using /dev/vdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) 
```
Enter unit s and press Enter to set the measurement unit of the disk to sector.

Enter p and press Enter to view the disk partition information.

Information similar to the following is displayed:

(parted) unit s
(parted) p
Error: The backup GPT table is not at the end of the disk, as it should be.  This might mean that another operating system believes the
disk is smaller.  Fix, by moving the backup to the end (and removing the old backup)?
Fix/Ignore/Cancel? Fix
Warning: Not all of the space available to /dev/vdb appears to be used, you can fix the GPT to use all of the space (an extra 104857600
blocks) or continue with the current setting?
Fix/Ignore? Fix
Model: Virtio Block Device (virtblk)
Disk /dev/vdb: 314572800s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start  End         Size        File system  Name  Flags
 1      2048s  209713151s  209711104s  ext4         test

(parted)

In the command output, take note of the partition's end sector. In this example, the end sector of the /dev/vdb1 partition is 209713151s.

If the following error information is displayed, enter Fix.
```
Error: The backup GPT table is not at the end of the disk, as it should be.  This might mean that another operating system believes the
disk is smaller.  Fix, by moving the backup to the end (and removing the old backup)?
```
The GPT partition table information is stored at the start of the disk. To reduce the risk of damages, a backup of the information is saved at the end of the disk. When you expand the disk capacity, the end of the disk changes accordingly. In this case, enter Fix to move the backup file of the information to new disk end.

If the following warning information is displayed, enter Fix.

Warning: Not all of the space available to /dev/vdb appears to be used, you can fix the GPT to use all of the space (an extra 104857600
blocks) or continue with the current setting?
Fix/Ignore? Fix

Enter Fix as prompted. The system automatically sets the GPT partition style for the additional space.

Run the following command and press Enter:

mkpart Partition name Start sector End sector

In this example, run the following command:

mkpart data 209713152s 100%

In this example, the additional space is used to create a new partition. In 4, the end sector of partition dev/vdb1 is 209713151s. Therefore, the start sector of the new partition dev/vdb2 is set to 209713152s and the end sector 100%. This start and end sectors are for reference only. You can plan the number of partitions and partition size based on service requirements.
Information similar to the following is displayed:
```
(parted) mkpart data 209713152s 100%
(parted) 
```
The maximum sector can be obtained in either of the following ways:
- Query the disk's maximum end sector. For details, see 2 to 4.
- Enter -1s or 100%, and the value displayed is the maximum end sector.

Enter p and press Enter to view the new partition.

Information similar to the following is displayed:

(parted) p
Model: Virtio Block Device (virtblk)
Disk /dev/vdb: 314572800s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start       End         Size        File system  Name  Flags
 1      2048s       209713151s  209711104s  ext4         test
 2      209713152s  314570751s  104857600s               data

(parted)

Enter q and press Enter to exit parted.
Information similar to the following is displayed:
```
(parted) q
Information: You may need to update /etc/fstab.
```
You can set automatic disk mounting by updating the /etc/fstab file. Before updating the file, set the file system format for the partition and mount the partition on the mount point.

Run the following command to set the file system format for the new partition:

mkfs -t File system Disk partition

Sample command of the ext* file system:

mkfs -t ext4 /dev/vdb2

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# mkfs -t ext4 /dev/vdb2
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
3276800 inodes, 13107200 blocks
655360 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2162163712
400 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

Sample command of the xfs file system:

mkfs -t xfs /dev/vdb2

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# mkfs -t xfs /dev/vdb2 
meta-data=/dev/vdb2              isize=512     agcount=4, agsize=3276800 blks
         =                       sectsz=512    attr=2, projid32bit=1
         =                       crc=1         finobt=0, sparse=0
data     =                       bsize=4096    blocks=13107200, imaxpct=25
         =                       sunit=0       swidth=0 blks
naming   =version2               bsize=4096    ascii-ci=0 ftype=1
log      =internal log           bsize=4096    blocks=6400, version=2
         =                       sectsz=512    sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096    blocks=0, rtextents=0

The formatting takes a while, and you need to observe the system running status. Once done is displayed in the command output, the formatting is complete.

(Optional) Run the following command to create a mount point:

Perform this step if you want to mount the partition on a new mount point.

mkdir Mount point

In this example, run the following command to create the /mnt/test mount point:

mkdir /mnt/test
Run the following command to mount the new partition:

mount Disk partition Mount point

In this example, run the following command to mount the new partition /dev/vdb2 on /mnt/test:

mount /dev/vdb2 /mnt/test

If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.

Run the following command to view the mount result:

df -TH

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# df -TH
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      ext4       43G  1.9G   39G   5% /
devtmpfs       devtmpfs  2.0G     0  2.0G   0% /dev
tmpfs          tmpfs     2.0G     0  2.0G   0% /dev/shm
tmpfs          tmpfs     2.0G  9.1M  2.0G   1% /run
tmpfs          tmpfs     2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs          tmpfs     398M     0  398M   0% /run/user/0
/dev/vdb1      ext4      106G   63M  101G   1% /mnt/sdc
/dev/vdb2      ext4       53G   55M   50G   1% /mnt/test

Extending an Existing GPT Partition

During an expansion, the additional space is added to the end of the disk. Therefore, if the disk has multiple partitions, the additional space can only be allocated to the partition at the disk end.

Run the following command to view the disk partition information:

lsblk
Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    253:0    0   40G  0 disk
└─vda1 253:1    0   40G  0 part /
vdb    253:16   0  230G  0 disk
├─vdb1 253:17   0  100G  0 part /mnt/sdc
└─vdb2 253:18   0   50G  0 part /mnt/test
```
View the /dev/vdb capacity and check whether the additional space is included.
- If the additional space is not included, refresh the capacity according to Extending SCSI Data Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0).
- If the additional space is included, go to 2.
Run the following command to unmount the partition:

umount Disk partition

In this example, run the following command:

umount /dev/vdb2

Run the following command to view the unmount result:

lsblk

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    253:0    0   40G  0 disk
└─vda1 253:1    0   40G  0 part /
vdb    253:16   0  230G  0 disk
├─vdb1 253:17   0  100G  0 part /mnt/sdc
└─vdb2 253:18   0   50G  0 part

Run the following command to enter parted:

parted Disk

In this example, run the following command:

parted /dev/vdb
Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# parted /dev/vdb
GNU Parted 3.1
Using /dev/vdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted)
```
Enter unit s and press Enter to set the measurement unit of the disk to sector.

Enter p and press Enter to view the disk partition information.

Information similar to the following is displayed:

(parted) unit s
(parted) p
Error: The backup GPT table is not at the end of the disk, as it should be.  This might mean that another operating system believes the
disk is smaller.  Fix, by moving the backup to the end (and removing the old backup)?
Fix/Ignore/Cancel? Fix
Warning: Not all of the space available to /dev/vdb appears to be used, you can fix the GPT to use all of the space (an extra 167772160
blocks) or continue with the current setting?
Fix/Ignore? Fix
Model: Virtio Block Device (virtblk)
Disk /dev/vdb: 482344960s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start       End         Size        File system  Name  Flags
 1      2048s       209713151s  209711104s  ext4         test
 2      209713152s  314570751s  104857600s  ext4         data

(parted)

Take note of the start and end sectors of the /dev/vdb2 partition. These values will be used during the partition recreation. In this example, the partition's start sector is 209713152s, and its end sector is 314570751s.

If the following error information is displayed, enter Fix.
```
Error: The backup GPT table is not at the end of the disk, as it should be.  This might mean that another operating system believes the
disk is smaller.  Fix, by moving the backup to the end (and removing the old backup)?
```
The GPT partition table information is stored at the start of the disk. To reduce the risk of damages, a backup of the information is saved at the end of the disk. When you expand the disk capacity, the end of the disk changes accordingly. In this case, enter Fix to move the backup file of the information to new disk end.

If the following warning information is displayed, enter Fix.

Warning: Not all of the space available to /dev/vdb appears to be used, you can fix the GPT to use all of the space (an extra 104857600
blocks) or continue with the current setting?
Fix/Ignore? Fix

Enter Fix as prompted. The system automatically sets the GPT partition style for the additional space.

Enter rm and the partition number, and then press Enter. In this example, partition number 2 is used.
Information similar to the following is displayed:
```
(parted) rm
Partition number? 2
(parted)
```
Run the following command to recreate the partition and press Enter:

mkpart Partition name Start sector End sector

In this example, run the following command:

mkpart data 209713152s 100%
- Ensure that the entered start sector is the same as the partition had before. In this example, start sector 209713152s is recorded in 6. Therefore, enter 209713152s.
- Ensure that the entered end sector is smaller than the partition had before. In this example, the end sector recorded in 6 is 314570751s, and all the additional space needs to be allocated to dev/vdb2. Therefore, enter 100%.
Information similar to the following is displayed:
```
(parted) mkpart data 209713152s 100%
(parted)
```
Data will be lost if the following operations are performed:
- Select a start sector other than the partition had before.
- Select an end sector smaller than the partition had before.

Enter p and press Enter to view the partition information.

Information similar to the following is displayed:

(parted) p
Model: Virtio Block Device (virtblk)
Disk /dev/vdb: 482344960s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start       End         Size        File system  Name  Flags
 1      2048s       209713151s  209711104s  ext4         test
 2      209713152s  482342911s  272629760s  ext4         data

(parted)

Enter q and press Enter to exit parted.
Information similar to the following is displayed:
```
(parted) q
Information: You may need to update /etc/fstab.
```
You can set automatic disk mounting by updating the /etc/fstab file. Before updating the file, set the file system format for the partition and mount the partition on the mount point.
Perform the following operations based on the file system of the disk:
- For the ext* file system
  1. Run the following command to check the correctness of the file system on the partition:
    e2fsck -f Disk partition
    
    In this example, run the following command:
    
    e2fsck -f /dev/vdb2
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# e2fsck -f /dev/vdb2
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vdb2: 11/3276800 files (0.0% non-contiguous), 251790/13107200 blocks
```
  2. Run the following command to extend the file system of the partition:
    resize2fs Disk partition
    
    In this example, run the following command:
    
    resize2fs /dev/vdb2
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# resize2fs /dev/vdb2
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vdb2 to 34078720 (4k) blocks.
The filesystem on /dev/vdb2 is now 34078720 blocks long.
```
  3. (Optional) Run the following command to create a mount point:
    Perform this step if you want to mount the partition on a new mount point.
    
    mkdir Mount point
    
    In this example, run the following command to create the /mnt/test mount point:
    
    mkdir /mnt/test
  4. Run the following command to mount the partition:
    mount Disk partition Mount point
    
    In this example, run the following command to mount the partition /dev/vdb2 on /mnt/test:
    
    mount /dev/vdb2 /mnt/test
    
    If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.
- For the xfs file system
  1. (Optional) Run the following command to create a mount point:
    Perform this step if you want to mount the partition on a new mount point.
    
    mkdir Mount point
    
    In this example, run the following command to create the /mnt/test mount point:
    
    mkdir /mnt/test
  2. Run the following command to mount the partition:
    mount Disk partition Mount point
    
    In this example, run the following command to mount the partition /dev/vdb2 on /mnt/test:
    
    mount /dev/vdb2 /mnt/test
    
    If the new partition is mounted on a directory that is not empty, the subdirectories and files in the directory will be hidden. Therefore, you are advised to mount the new partition on an empty directory or a new directory. If the new partition must be mounted on a directory that is not empty, move the subdirectories and files in this directory to another directory temporarily. After the partition is successfully mounted, move the subdirectories and files back.
  3. Run the following command to extend the file system of the partition:
    sudo xfs_growfs Disk partition
    
    In this example, run the following command:
    
    sudo xfs_growfs /dev/vdb2
    
    Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# sudo xfs_growfs /dev/vdb2 
meta-data=/dev/vdb2              isize=512     agcount=4, agsize=3276800 blks
         =                       sectsz=512    attr=2, projid32bit=1
         =                       crc=1         finobt=0, spinodes=0
data     =                       bsize=4096    blocks=13107200, imaxpct=25
         =                       sunit=0       swidth=0 blks
naming   =version2               bsize=4096    ascii-ci=0 ftype=1
log      =internal               bsize=4096    blocks=6400, version=2
         =                       sectsz=512    sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096    blocks=0, rtextents=0
data blocks changed from 13107200 to 34078720.
```

Run the following command to view the mount result:

df -TH

Information similar to the following is displayed:

[root@ecs-test-0001 ~]# df -TH
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      ext4       43G  1.9G   39G   5% /
devtmpfs       devtmpfs  2.0G     0  2.0G   0% /dev
tmpfs          tmpfs     2.0G     0  2.0G   0% /dev/shm
tmpfs          tmpfs     2.0G  9.1M  2.0G   1% /run
tmpfs          tmpfs     2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs          tmpfs     398M     0  398M   0% /run/user/0
/dev/vdb1      ext4      106G   63M  101G   1% /mnt/sdc
/dev/vdb2      ext4      138G   63M  131G   1% /mnt/test

Setting Automatic Mounting at System Start

Modify the fstab file to set automatic disk mounting at server start. You can also set automatic mounting for the servers containing data. This operation will not affect the existing data.

The following procedure shows how to set automatic disk mounting at server start by using UUIDs to identify disks in the fstab file. You are advised not to use device names to identify disks in the file because a device name may change (for example, from /dev/vdb1 to /dev/vdb2) during the server stop or start, resulting in improper server running after restart.

UUID is the unique character string for disk partitions in a Linux system.

Run the following command to query the partition UUID:

blkid Disk partition

In this example, run the following command to query the UUID of the /dev/vdb1 partition:

blkid /dev/vdb1

Information similar to the following is displayed:
```
[root@ecs-test-0001 ~]# blkid /dev/vdb1
/dev/vdb1: UUID="0b3040e2-1367-4abb-841d-ddb0b92693df" TYPE="ext4"
```
The UUID of the /dev/vdb1 partition is displayed.
Run the following command to open the fstab file using the vi editor:

vi /etc/fstab
Press i to enter editing mode.
Move the cursor to the end of the file and press Enter. Then, add the following information:
```
UUID=0b3040e2-1367-4abb-841d-ddb0b92693df /mnt/sdc                ext4    defaults        0 2
```
The preceding content is used for reference only. Add the information that is used in the environment. The parameters are described as follows:
- The first column indicates the partition UUID obtained in 1.
- The second column indicates the directory on which the partition is mounted. You can query the mount point using the df -TH command.
- The third column indicates the file system format of the partition. You can query the file system format using the df -TH command.
- The fourth column indicates the partition mount option. Normally, this parameter is set to defaults.
- The fifth column indicates the Linux dump backup option.
  - 0: Linux dump backup is not used. Normally, dump backup is not used, and you can set this parameter to 0.
  - 1: Linux dump backup is used.
- The sixth column indicates the fsck option, that is, whether to use fsck to check the attached disk during startup.
  - 0: not use fsck.
  - If the mount point is the root partition (/), this parameter must be set to 1.
    When this parameter is set to 1 for the root partition, this parameter for other partitions must start with 2 because the system checks the partitions in the ascending order of the values.
Press Esc, enter :wq, and press Enter.

The system saves the configurations and exits the vi editor.
Perform the following operations to verify the automatic mounting function:
1. Run the following command to unmount the partition:
  umount Disk partition
  
  In this example, run the following command:
  
  umount /dev/vdb1
2. Run the following command to reload all the content in the /etc/fstab file:
  mount -a
3. Run the following command to query the file system mounting information:
  mount | grep Mount point
  
  In this example, run the following command:
  
  mount | grep /mnt/sdc
  
  If information similar to the following is displayed, automatic mounting has been configured:
```
root@ecs-test-0001 ~]# mount | grep /mnt/sdc
/dev/vdb1 on /mnt/sdc type ext4 (rw,relatime,data=ordered)
```

Parent topic: Extending Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)

Previous topic: Extending System Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)

Next topic: Extending SCSI Data Disk Partitions and File Systems (Linux Kernel Earlier Than 3.6.0)

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