# Partition and File System Extension Preparations (Linux)

Before extending the disk partition and file system, you must check the disk partition style and file system format, and then select the appropriate operation accordingly.

1. To view the disk partition style, see the following methods:
   - Method 1: Check Partition Style and File System Format Using fdisk
   - Method 2: Check Partition Style and File System Format Using parted
2. To select the appropriate operation, see Table 1.

   Table 1 Disk partition and file system extension scenarios
   Disk | Scenario | Method
   --- | --- | ---
   System disk | Create a new MBR partition with the additional space. | Creating a New MBR Partition

   Allocate the additional space to an existing MBR partition.

   - Extending an Existing MBR Partition (Kernel Version Later Than 3.6.0)
   - Extending an Existing MBR Partition (Kernel Version Earlier Than 3.6.0)

   Data disk | Create a new MBR partition with the additional space. | Creating a New MBR Partition
   Allocate the additional space to an existing MBR partition. | Extending an Existing MBR Partition
   Create a new GPT partition with the additional space. | Creating a New GPT Partition
   Allocate the additional space to an existing GPT partition. | Extending an Existing GPT Partition
   SCSI data disk | Create a new MBR partition with the additional space. | Creating a New MBR Partition
   Allocate the additional space to an existing MBR partition. | Extending an Existing MBR Partition

   The maximum disk capacity that MBR supports is 2 TB, and the disk space exceeding 2 TB cannot be used.

   If your disk uses MBR and you need to expand the disk capacity to over 2 TB, change the partition style from MBR to GPT. Ensure that the disk data has been backed up before changing the partition style because services will be interrupted and data on the disk will be cleared during this change.

#### Method 1: Check Partition Style and File System Format Using fdisk

1. Run the following command to view all the disks attached to the server:

   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

   In this example, data disk /dev/vdb already has partition /dev/vdb1 before capacity expansion, and the additional 50 GB added has not been allocated yet. Therefore, /dev/vdb has 150 GB, and /dev/vdb1 has 100 GB.

2. Run the following command to view the current disk partition style:

   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

   The value in the System column indicates the disk partition style. Value Linux indicates the MBR partition style. Value GPT indicates the GPT partition style.

   - If the disk partitions displayed are inconsistent with those obtained in 1, the partition that is not displayed uses the GPT partition style and has unallocated space. In this case, you cannot query all the partition information using the fdisk -l command. Go to Method 2: Check Partition Style and File System Format Using parted.
   - If the disk partitions displayed are consistent with those obtained in 1, continue with the following operations.
3. Run the following command to view the partition's file system format:

   blkid Disk partition

   In this example, run the following command:

   blkid /dev/vdb1

   In the command output, the TYPE value is ext4, indicating that /dev/vdb1's file system format is ext4.

4. Run the following command to view the file system status:

   ext*: e2fsck -n Disk partition

   xfs: xfs_repair -n Disk partition

   In this example, the ext4 file system is used. Therefore, run the following command:

   e2fsck -n /dev/vdb1

   Information similar to the following is displayed:

       [root@ecs-test-0001 ~]# e2fsck -n /dev/vdb1
       e2fsck 1.42.9 (28-Dec-2013)
       Warning!  /dev/vdb1 is mounted.
       Warning: skipping journal recovery because doing a read-only filesystem check.
       /dev/vdb1: clean, 11/6553600 files, 459544/26214144 blocks

   If the file system status is clean, the file system status is normal. Otherwise, rectify the faulty and then perform the capacity expansion.

#### Method 2: Check Partition Style and File System Format Using parted

1. Run the following command to view all the disks attached to the server:

   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

   In this example, data disk /dev/vdb already has partition /dev/vdb1 before capacity expansion, and the additional 50 GB added has not been allocated yet. Therefore, /dev/vdb has 150 GB, and /dev/vdb1 has 100 GB.

2. Run the following command and enter p to view the disk partition style:

   parted Disk

   For example, run the following command to view /dev/vdb's partition style:

   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) 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: 161GB
       Sector size (logical/physical): 512B/512B
       Partition Table: gpt
       Disk Flags:

       Number  Start   End    Size   File system  Name  Flags
        1      1049kB  107GB  107GB  ext4         test

       (parted)

   In the command output, parameter Partition Table indicates the disk partition style. Value msdos indicates the MBR partition style, and value gpt indicates the GPT partition style.
   - 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.

3. Enter q and press Enter to exit parted.

Parent topic: Extending Disk Partitions and File Systems (Linux)