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 method for allocating the additional space varies with the server OS. This section is used for reference only. For detailed operations and differences, see the corresponding OS documents.
- Creating a New MBR Partition
- Extending an Existing MBR Partition
- Creating a New GPT Partition
- Extending an Existing GPT Partition
Performing the expansion operations with caution. Misoperation may lead to data loss or exceptions. Therefore, you are advised to back up the disk data using CBR or snapshots before expansion. For details about using CBR, see Managing EVS Backups. For details about using snapshots, see Creating a Snapshot.
Prerequisites
- You have expanded the disk capacity and attached the 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 the Elastic Cloud Server User Guide.
- For how to log in to a BMS, see the Bare Metal Server User Guide.
Constraints
The additional space cannot be added to the root partition of a data disk. To extend the root partition, expand the system disk instead.
Creating a New MBR Partition
Originally, data disk /dev/vdb has 100 GiB and one partition (/dev/vdb1), and then 50 GiB is added to the disk. The following procedure shows you how to create a new MBR partition /dev/vdb2 with this 50 GiB.
- 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:
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:
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.
- Sample command of the ext* file system:
- (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 GiB and two partitions (/dev/vdb1 and /dev/vdb2), and then 80 GiB is added to the disk. The following procedure shows you how to add this 80 GiB 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 Partitions and File Systems for SCSI Disks (Linux).
- 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:
- 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):
- 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 d and press Enter to delete the partition.
- 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
- Run the following command to check the correctness of the file system on the 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
- Run the following command to extend the file system of the 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.
- (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 partition:
mount Disk partition Mount point
In this example, run the following command to mount 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 check the correctness of the file system on the partition:
- For the xfs file system
- (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 partition:
mount Disk partition Mount point
In this example, run the following command to mount 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 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.
- (Optional) Run the following command to create a mount point:
- For the ext* file system
- 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
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.
Creating a New GPT Partition
Originally, data disk /dev/vdb has 100 GiB and one partition (/dev/vdb1), and then 50 GiB is added to the disk. The following procedure shows you how to create a new GPT partition /dev/vdb2 with this 50 GiB.
- 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 damage, 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.
- If the following error information is displayed, enter Fix.
- 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)
- 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:
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:
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.
- Sample command of the ext* file system:
- (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 GPT 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 GiB and two partitions (/dev/vdb1 and /dev/vdb2), and then 80 GiB is added to the disk. The following procedure shows you how to add this 80 GiB to the existing GPT 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:
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 Partitions and File Systems for SCSI Disks (Linux).
- 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 damage, 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.
- If the following error information is displayed, enter Fix.
- 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 greater 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
- Run the following command to check the correctness of the file system on the 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
- Run the following command to extend the file system of the 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.
- (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 partition:
mount Disk partition Mount point
In this example, run the following command to mount 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 check the correctness of the file system on the partition:
- For the xfs file system
- (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 partition:
mount Disk partition Mount point
In this example, run the following command to mount 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 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.
- (Optional) Run the following command to create a mount point:
- For the ext* file system
- 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
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.
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
- 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:
- Run the following command to unmount the partition:
In this example, run the following command:
umount /dev/vdb1
- Run the following command to reload all the content in the /etc/fstab file:
mount -a
- Run the following command to query the file system mounting information:
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)
- Run the following command to unmount the partition: