Elastic Compute Service:Initialize a data disk whose size does not exceed 2 TiB on a Linux instance

Procedure

In the following examples, an ECS instance that runs Alibaba Cloud Linux 3 is used. The commands that you can run to initialize a data disk may vary based on the instance operating system.

Step 1: Connect to the Linux ECS instance and view the data disks

1. Connect to the Linux ECS instance.

   For more information, see Connect to a Linux instance by using a password or key.

2. Run the following command to obtain the device names of the data disks:

   sudo fdisk -lu

   The following command output indicates that two disks are attached to the Linux ECS instance:

   • ①: /dev/vda is the system disk, which is created together with the instance and already initialized.

   • ②: /dev/vdb is a data disk, which needs to be initialized.

   

(Conditionally required) Step 2: Create partitions on the data disk

If you want to individually store, maintain, and manage data in different categories, such as applications, files, and storage data, in different partitions, perform this step to create partitions on the data disk. If you want to use the data disk as a raw disk, you can create a file system for the disk without the need to partition the disk. For more information, see Create a file system on a raw disk.

Step 3: Create and mount a file system

You must create and mount file systems on a data disk regardless of whether the disk is partitioned before the disk can be recognized by the operating system of the ECS instance to which the disk is attached and be used as expected. The types of file systems that you can create vary based on the partition size. Create a file system that meets your business requirements.

1. Run the following command to install e2fsprogs:

   sudo yum install -y e2fsprogs

   Note

   The yum command used in this step is applicable to Linux distributions such as CentOS. For other Linux distributions, modify the command based on your package management software. For example, run the apt-get install <Package name> command for Debian or Ubuntu.

2. Create a file system. In the examples, an Ext4 file system and an XFS file system are created.

   Create an Ext4 file system

   sudo mkfs -t ext4 /dev/vdb1

   /dev/vdb1 is the partition name of the data disk. Replace /dev/vdb1 with an actual partition name.

   Note

   • If an error occurs when you create an Ext4 file system for a 16 TiB data disk, the version of the e2fsprogs package that you use may be earlier than 1.42. Upgrade the version of e2fsprogs to version 1.42 or later. For more information, see the How do I upgrade e2fsprogs on a Linux instance? section in this topic.

   • The lazy init feature of Ext4 file systems affects the I/O performance of data disks. You can disable the lazy init feature of Ext4 file systems. For more information, see the How do I disable the lazy init feature on a Linux instance? section in this topic.

   The following command output is returned, which indicates that an Ext4 file system is created for the /dev/vdb1 partition of the data disk.

   

   Create an XFS file system

   sudo mkfs -t xfs /dev/vdb1

   /dev/vdb1 is the partition name of the data disk. Replace /dev/vdb1 with an actual partition name.

   The following command output is returned, which indicates that an XFS file system is created for the /dev/vdb1 partition of the data disk.

   

3. Run the following command to mount the file system.

   Note

   You can run the mount command with different mount parameters to mount Ext4 file systems based on your business requirements, including data security requirements and performance requirements. For more information, see Mount Ext4 file systems with mount command options.

   sudo mount /dev/vdb1 /mnt

   Take note of the following parameters in the command:

   • /dev/vdb1 is the partition name of the data disk. Replace /dev/vdb1 with an actual partition name.

   • /mnt is the mount point of the partition. Replace /mnt with an existing directory. Alternatively, run the sudo mkdir -p <New directory> command to create a directory, and then replace /mnt with the new directory. Sample command: sudo mkdir -p /data.

4. Run the following command to check whether the file system is mounted as expected:

   df -Th

   The following command output is returned. If the file system is mounted, information about the new file system is displayed.

   

Step 4: Configure the disk partition to automatically mount on instance startup

1. Run the following command to back up the etc/fstab file:

   sudo cp /etc/fstab /etc/fstab.bak

2. Write information about the new partition to the /etc/fstab file.

   sudo sh -c "echo `blkid /dev/vdb1 | awk '{print \$2}' | sed 's/\"//g'` /mnt ext4 defaults 0 0 >> /etc/fstab"

   Take note of the following parameters in the command:

   • /dev/vdb1: the partition name of the data disk. Replace /dev/vdb1 with an actual partition name. You can run the df -Th command to obtain the names of partitions.

   • /mnt: the mount point of the partition. Replace /mnt with an actual mount point. You can run the df -Th command to obtain the mount points of partitions.

   • ext4: the file system type of the partition. Replace ext4 with the type of the file system that you created. You can run the df -Th command to obtain the file system types of partitions.

   • defaults: the mount parameter of the file system. Specify mount parameters based on your business requirements. For more information, see fstab.

   Note

   The Ubuntu 12.04 operating system does not support barriers. You must run the sudo sh -c "echo `blkid /dev/vdb1 | awk '{print $2}' | sed 's/\"//g'` /mnt ext4 barrier=0 0 0 >> /etc/fstab" command to write information about the disk partition to the /etc/fstab file.

3. (Conditionally required) If a data disk has multiple consecutive partitions, run a command specific to each partition to write partition information to the /etc/fstab file.

   For example, for the /dev/vdb data disk that has the /dev/vdb1 and /dev/vdb2 partitions, separately run the following commands:

   sudo sh -c "echo `blkid /dev/vdb1 | awk '{print \$2}' | sed 's/\"//g'` <Mount point of the /dev/vdb1 partition> <File system type of the /dev/vdb1 partition> defaults 0 0 >> /etc/fstab"
   sudo sh -c "echo `blkid /dev/vdb2 | awk '{print \$2}' | sed 's/\"//g'` <Mount point of the /dev/vdb2 partition> <File system type of the /dev/vdb2 partition> defaults 0 0 >> /etc/fstab"

4. Run the following command to view information about the new partition in the /etc/fstab file:

   cat /etc/fstab

   The following command output is returned, which contains information about the /dev/vdb1 partition.

   

   Note

   If the information about the partition contained in the command output is incorrect, you can delete the incorrect partition information from the /etc/fstab file and add the correct information about the partition to the file. For more information, see Configure UUIDs in the fstab file to automatically attach data disks.

5. Run the following commands to check whether the partition is automatically mounted:

   sudo umount /dev/vdb1
   sudo mount -a
   mount | grep /mnt

   The following command output is returned. If the file system of the partition is mounted, the mount information of the file system is displayed.

   

FAQ about disk initialization

mkfs.ext4: Size of device /dev/vdb too big to be expressed in 32 bits using a blocksize of 4096.            

sudo mke2fs -O 64bit,has_journal,extents,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize -E lazy_itable_init=0,lazy_journal_init=0 /dev/vdb1

References

• If your disk is larger than 2 TiB in size and you want to store and manage data in different categories in different partitions on the disk, initialize the disk. For more information, see the Initialize a data disk whose size exceeds 2 TiB on a Linux instance section of the "Initialize a data disk whose size exceeds 2 TiB" topic.

• If you want to use a disk as a raw disk without the need to partition the disk, you need to only create a file system for the raw disk when you initialize the disk. For more information, see Create a file system on a raw disk.

• If a disk does not have sufficient storage space, you can extend the capacity of the disk to increase the storage space. For information about how to extend a disk, see Overview.