Extending Partitions and File Systems Offline (Linux Data Disk)

Prerequisites

• You have expanded the EVS disk capacity and attached the disk to a server on the console. For details, see Step 1: Expand Disk Capacity.
• You have backed up the disk data using snapshots. This prevents data loss caused by misoperations. For how to back up data using snapshots, see Creating an EVS Snapshot.
• 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 a BMS.

Checking the Partition Table Format and File System

1. Check the partition table format and file system.
   1. Check the partition table format of the data disk.

      sudo fdisk -lu /dev/vdb

      In this example, the /dev/vdb data disk is formatted into the /dev/vdb1 partition. The command output is as follows:

      Device    Boot  Start    End   Sectors  Size  Id  Type 
      /dev/vdb1  *    2048 83886046 83883999   40G  83  Linux

      • If the value under Type is Linux, the data disk uses the MBR partition table format.
      • If the value under Type is GPT, the data disk uses the GPT partition table format.
   2. Check the file system type of the partition.

      blkid /dev/vdb1

      [test@ecs-test-0001 ~]# blkid /dev/vdb1 /dev/vdb1: UUID="b9a07b7b-9322-4e05-ab9b-14b8050cd8cc" TYPE="ext4"

      The value under TYPE indicates the file system type.

2. Check whether the file system status is normal.
   If the file system status is abnormal, rectify the fault and then perform subsequent operations.

   Table 1 Status check

   File System Type	Command	Status Description
   ext*	sudo e2fsck -n /dev/vdb1	The file system status is normal if its value is clean.
   xfs	sudo xfs_repair -n /dev/vdb1
   btrfs	sudo btrfsck /dev/vdb1	The file system status is normal if it contains "found xxxx bytes used err is 0".

3. Select a method to extend the partitions and file systems.

   Determine the operation based on the partition table format and file system information.

   Expansion Scenario	Operations
   The data disk has been partitioned, and a file system has been created.	To extend an existing MBR partition of the data disk, see Extending an Existing MBR Partition. To create a new MBR partition on the data disk, see Creating a New MBR Partition. To extend an existing GPT partition of the data disk, see Extending an Existing GPT Partition. To create a new GPT partition on the data disk, see Creating a New GPT Partition.
   The data disk is brand new, has not been partitioned, and has no file system created on.	Expand the disk capacity on the console. Then, perform operations by referring to Initializing EVS Data Disks.
   The data disk is used as a raw device, has a file system created on, but is not partitioned.	Expand the disk capacity on the console. Then, perform operations by referring to Extending the File System on a Raw Device.
   The data disk is not attached to any server.	Attach the data disk to a server. Then, complete the expansion by referring to operations provided in this document.

   

   • The maximum disk capacity that MBR supports is 2 TiB, and the disk space in access of 2 TiB cannot be used. To prevent data loss, you are advised to create an EVS disk greater than 2 TiB, format it with GPT, and then copy data from the MBR partition to the new GPT partition.
   • If the expansion fails due to an error of the formatting tool, you can upgrade the tool version in advance or uninstall the tool and reinstall it.

Extending an Existing MBR Partition

To prevent data loss, you are advised not to directly extend the partition or file system of an existing partition. Instead, unmount the partition, extend the partition and file system, and then remount the partition. The operation varies depending on the kernel version of the Linux server:

• If the kernel version is earlier than 3.6, unmount the partition, modify the partition table, and then extend the file system.
• If the kernel version is 3.6 or later, modify the partition table, notify the kernel to update the partition table, and then extend the file system.

Creating a New MBR Partition

To allocate the additional space to a new MBR partition, perform the following steps in the server OS:

1. Create a new partition.

   sudo fdisk -u /dev/vdb

   1. Enter p and press Enter to print the partition table information.
   2. Enter n and press Enter to create a new partition.
   3. Enter p and press Enter to create a primary partition.
   4. Enter 2 and press Enter to set a partition number. Partition number 2 is used in this example.
   5. Use the default start sector and press Enter.
   6. Use the default end sector and press Enter.
   7. Enter w and press Enter to write the partition result and exit.

   The following example shows how to use fdisk to allocate the additional 20 GiB to a new MBR partition /dev/vdb2:

   [test@ecs-test-0001 ~]# sudo fdisk -u /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): p
   
   Disk /dev/vdb: 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/vdb1            2048    41943039    20970496   83  Linux
   
   Command (m for help): n
   Partition type:
      p   primary (1 primary, 0 extended, 3 free)
      e   extended
   Select (default p): p
   Partition number (2-4, default 2): 2
   First sector (41943040-83886079, default 41943040):
   Using default value 41943040
   Last sector, +sectors or +size{K,M,G} (41943040-83886079, default 83886079):
   Using default value 83886079
   Partition 2 of type Linux and of size 20 GiB is set
   
   Command (m for help): w
   The partition table has been altered!
   
   Calling ioctl() to re-read partition table.
   Syncing disks.

2. Check the partition result.

   lsblk /dev/vdb

3. Create a file system.
   • ext4 file system:

     sudo mkfs.ext4 /dev/vdb2

   • xfs file system:

     sudo mkfs.xfs -f /dev/vdb2

   • btrfs file system:

     sudo mkfs.btrfs /dev/vdb2

4. Check the file system information.

   blkid /dev/vdb2

   [test@ecs-test-0001 ~]# blkid /dev/vdb2/dev/vdb2: UUID="0b3040e2-1367-4abb-841d-ddb0b92693df" TYPE="ext4"

5. Mount the partition.

   sudo mount /dev/vdb2 /mnt

6. Check the space and usage of the data disk.

   df -h

   If information about the new file system is displayed, the mount is successful.

Extending an Existing GPT Partition

To allocate the additional space to an existing GPT partition, perform the following steps in the server OS:

1. Check the data disk's mount information and then unmount the partition based on the returned information. Ensure that the partition is fully unmounted.

   Check the mount information.

   mount | grep "/dev/vdb"

   Unmount the desired partition.

   sudo umount /dev/vdb1

   Check the operation result.

   mount | grep "/dev/vdb"

   The command output is as follows:

   [test@ecs-test-0001 ~]# mount | grep "/dev/vdb" /dev/vdb1 on /mnt type ext4 (rw,relatime,data=ordered) 
   [test@ecs-test-0001 ~]# sudo umount /dev/vdb1 
   [test@ecs-test-0001 ~]# mount | grep "/dev/vdb"

2. Use parted to allocate space to the existing GPT partition.
   1. Enter the parted tool.

      sudo parted /dev/vdb

      Enter help to find out parted's usage instructions if needed.

   2. Check the partition information and take note of the partition number as well as the start and end sectors of the existing partition.

      print

      If Fix/Ignore/Cancel? and Fix/Ignore? are displayed, enter Fix for both of them.

   3. Delete the existing partition. In this example, delete the partition whose partition number is 1.

      rm 1

   4. Re-create a primary partition. In this example, the start sector of the original partition is 1049kB, and all of the additional space is allocated to the new partition.

      mkpart primary 1049kB 100%

   5. Check whether the new partition is created.

      print

   6. Exit the Parted tool.

      quit

      The following example shows how to use Parted to extend an existing GPT partition to 3299GB:

      [test@ecs-test-0001 ~]# sudo parted /dev/vdb
      GNU Parted 3.1
      Using /dev/vdb
      Welcome to GNU Parted! Type 'help' to view a list of commands.
      (parted) print
      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 4294967296 blocks) or continue
      with the current setting?
      Fix/Ignore? Fix
      Model: Virtio Block Device (virtblk)
      Disk /dev/vdb: 3299GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      Disk Flags:
      
      Number  Start   End     Size    File system  Name     Flags
       1      1049kB  1100GB  1100GB  ext4         primary
      
      (parted) rm 1
      (parted) mkpart primary 1049kB 100%
      (parted) print
      Model: Virtio Block Device (virtblk)
      Disk /dev/vdb: 3299GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      Disk Flags:
      
      Number  Start   End     Size    File system  Name     Flags
       1      1049kB  3299GB  3299GB  ext4         primary
      
      (parted) quit
      Information: You may need to update /etc/fstab.

3. Check the file system consistency.

   sudo fsck -f /dev/vdb1

   The command output is as follows:

   [test@ecs-test-0001 ~]# sudo fsck -f /dev/vdb1
   fsck from util-linux 2.23.2
   e2fsck 1.43.5 (04-Aug-2017)
   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/vdb1: 11/67108864 files (0.0% non-contiguous), 4265369/268434944 blocks

4. Extend the file system.
   • ext* file system (such as ext3 or ext4):
     1. Resize the ext* file system.

        sudo resize2fs /dev/vdb1

     2. Mount the partition on /mnt.

        sudo mount /dev/vdb1 /mnt

   • xfs file system:
     1. Mount the partition on /mnt.

        sudo mount /dev/vdb1 /mnt

     2. Resize the xfs file system.
        sudo xfs_growfs /mnt

        

        The xfs_growfs use mount points to identify devices, for example, xfs_growfs /mnt. You can run xfs_growfs --help to find out the usage of xfs_growfs of different versions.

   • btrfs file system:
     1. Mount the partition on /mnt.

        sudo mount /dev/vdb1 /mnt

     2. Resize the btrfs file system.

        sudo btrfs filesystem resize max /mnt

Creating a New GPT Partition

To allocate the additional space to a new GPT partition and use GPT thereafter, perform the following steps in the server OS: In the following example, the /dev/vdb data disk originally has 4.8 TiB and one partition /dev/vdb1. The disk is then expanded to 32 TiB. The following steps use parted to allocate the additional space to a new GPT partition /dev/vdb2.

1. Check information about the existing partition on the data disk.

   sudo fdisk -l

   The command output is as follows:

   [test@ecs-test-0001 ~]# sudo 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: 0x000b1b45
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/vda1   *        2048    83875364    41936658+  83  Linux
   WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.
   
   Disk /dev/vdb: 35184.4 GB, 35184372088832 bytes, 68719476736 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: gpt
   Disk identifier: BCE92401-F427-45CC-8B0D-B30EDF279C2F
   
   #         Start          End    Size  Type            Name
    1         2048  10307921919    4.8T  Microsoft basic mnt                    

2. Use parted to create a new partition and allocate space to the new partition.
   1. Enter the parted tool.

      sudo parted /dev/vdb

   2. Check the space to be allocated and take note of the sectors and size of the existing partition.

      print free

      In this example, the start sector of /dev/vdb1 is 1049kB, the end sector is 5278GB, and the size is 5278 GiB.

      (parted) print free
      Model: Virtio Block Device (virtblk)
      Disk /dev/vdb: 35.2TB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      Disk Flags:
      
      Number  Start   End     Size    File system  Name  Flags
              17.4kB  1049kB  1031kB  Free Space
       1      1049kB  5278GB  5278GB  ext4         mnt
              5278GB  35.2TB  29.9TB  Free Space                    

   3. Set the start sector and allocate space for the new partition. In this example, create the /dev/vdb2 partition and name it test. Use the original partition's start sector 5278GB as the start sector and allocate all of the additional space to the new partition.

      mkpart test 5278GB 100%

   4. Check whether the capacity (value under Size) changes.

      print

      The command output is as follows:

      (parted) print
      Model: Virtio Block Device (virtblk)
      Disk /dev/vdb: 35.2TB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      Disk Flags:
      
      Number  Start   End     Size    File system  Name  Flags
       1      1049kB  5278GB  5278GB  ext4         mnt
       2      5278GB  35.2TB  29.9TB               test                    

   5. Exit the Parted tool.

      quit

3. Create a file system for the new partition.
   • ext4 file system:

     sudo mkfs.ext4 /dev/vdb2

   • ext3 file system:

     sudo mkfs.ext3 /dev/vdb2

   • xfs file system:

     sudo mkfs.xfs -f /dev/vdb2

   • btrfs file system:

     sudo mkfs.btrfs /dev/vdb2

4. Check the changes on the partition size.

   sudo fdisk -l

5. Check the file system type on the storage device.

   blkid

6. Mount the new partition.

   sudo mount /dev/vdb2 /mnt

Extending the File System on a Raw Device

If no partition but only a file system is created on a data disk, perform the following steps to extend the file system:

1. Check the file system type on the storage device.

   df -Th

   In the command put, the value under Type indicates the file system type.

2. Run the corresponding command to extend the file system based on the file system type.
   • xfs file systems:

     Run the xfs_growfs command to extend the file system.

     sudo xfs_growfs /mnt

     In the command, /mnt is the mount point of the file system.

     

     The xfs_growfs use mount points to identify devices, for example, xfs_growfs /mnt. You can run xfs_growfs --help to find out the usage of xfs_growfs of different versions.

   • ext* and btrfs file systems:
     1. Check the data disk's mount information.

        mount | grep "/dev/vdb"

     2. Unmount the data disk.

        sudo umount /dev/vdb

     3. Check the operation result.

        mount | grep "/dev/vdb"

        The command output is as follows:

        [test@ecs-test-0001 ~]# mount | grep "/dev/vdb" 
        [test@ecs-test-0001 ~]# sudo umount /dev/vdb
        [test@ecs-test-0001 ~]# mount | grep "/dev/vdb"

     4. Extend the file system.
        • ext* file system:

          sudo resize2fs /dev/vdb

        • btrfs file system:

          sudo btrfs filesystem resize max /mnt

          In the command, /mnt is the mount point of the file system.

     5. Mount the disk on a mount point.

        sudo mount /dev/vdb /mnt

3. Check the capacity expansion result of the data disk.

   df -Th

   If the file system has been extended, the expansion is successful.