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

Procedure

Step 1: Connect to the Linux instance and view the data disk

1. Connect to the Linux 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 name of the data disk:

   fdisk -lu

   A command output similar to the following one is returned, which indicates that the instance has two disks: the system disk whose device name is /dev/vda and the new data disk whose device name is /dev/vdb.

Step 2: Create a partition on the data disk

Step 3: Create a file system for the partition

Create a file system for the new partition. Partition sizes vary based on file system types. Create a file system that suits your needs.

1. Run the following command to install the e2fsprogs tool:

   yum install -y e2fsprogs

   Note

   The yum command in this step is suitable for 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

   mkfs -t ext4 /dev/vdb1

   /dev/vdb1 is the partition name of the data disk. Replace it with the actual device name of your data disk.

   Important

   If an error is reported when you create an ext4 file system for a 16 TiB data disk, the version of the e2fsprogs package may be earlier than 1.42. Upgrade the version of e2fsprogs to 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.

   Create an xfs file system

   mkfs -t xfs /dev/vdb1

   /dev/vdb1 is the partition name of the data disk. Replace it with the actual device name of your data disk.

   A command output similar to the following one is returned. In this example, an ext4 file system is created for the /dev/vdb1 partition of the data disk.

Step 4: Configure the /etc/fstab file and mount the partition

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

   cp /etc/fstab /etc/fstab.bak

2. Write the information of the new partition to /etc/fstab.

   • If you are a root user, you can run the following command to modify /etc/fstab:

     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 it with the actual partition name.

     • /mnt: the mount point of the partition. Replace it with the actual mount point. You can mount the partition to an existing directory, or run the mkdir command to create a directory and then mount the partition to the new directory.

     • ext4: the file system type of the partition. Replace it with the type of the created file system.

     Note

     • The Ubuntu 12.04 operating system does not support barriers. You must run the echo `blkid /dev/vdb1 | awk '{print $2}' | sed 's/\"//g'` /mnt ext4 barrier=0 0 0 >> /etc/fstab command to write the information of the new partition to /etc/fstab. If your instance does not run an Ubuntu 12.04 operating system, ignore the note.

     • If a disk has multiple consecutive partitions, run a command specific to each partition to write partition information to /etc/fstab. For example, for the /dev/vdb data disk that has the /dev/vdb1 and /dev/vdb2 partitions, run the following commands separately:

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

   • If you are a common user, you can manually modify /etc/fstab. For more information, see Configure UUIDs in the fstab file to automatically attach data disks.

3. Run the following command to check the information of the new partition in /etc/fstab:

   cat /etc/fstab

   A command output similar to the following one is returned.

4. Run the following command to mount the file system that is configured in the /etc/fstab file. If the file system is correctly configured in /etc/fstab, no error is reported.

   mount -a

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

   df -h

   A command output similar to the following one is returned. If the file system is mounted, the information of the new file system is displayed.

FAQ about initializing disks

What do I do if a GPT partition is created on a disk but not aligned?

1. Run the following commands to query the parameters of the disk:

   cat /sys/block/vdb/queue/optimal_io_size
   cat /sys/block/vdb/queue/minimum_io_size
   cat /sys/block/vdb/alignment_offset
   cat /sys/block/vdb/queue/physical_block_size

2. Run the following command to re-create a primary partition:

   mkpart primary <Recommended sector number>s 100%

   The recommended sector number is calculated based on the following formula: <Recommended sector number>= (<optimal_io_size> + <alignment_offset>)/<physical_block_size>. For example, if the start sector number is 1024, you can run the mkpart primary 1024s 100% command to re-create a primary partition.

How do I upgrade e2fsprogs on a Linux instance?

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

Perform the following steps to install a later version of e2fsprogs. In this example, e2fsprogs 1.42.8 is used.

1. Run the following command to check the current e2fsprogs version:

   rpm -qa | grep e2fsprogs

   A command output similar to the following one is returned.

   

   If the version is earlier than 1.42, perform the following operations to upgrade e2fsprogs.

2. Run the following command to download e2fsprogs 1.42.8.

   You can visit the e2fsprogs website to obtain the latest software package.

   wget https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/v1.42.8/e2fsprogs-1.42.8.tar.gz --no-check-certificate

3. Compile the later version of e2fsprogs.

   1. Run the following command to decompress the software package:

      tar xvzf e2fsprogs-1.42.8.tar.gz

   2. Run the following command to go to the package directory:

      cd e2fsprogs-1.42.8

   3. Run the following command to generate the Makefile file:

      ./configure

   4. Run the following command to compile e2fsprogs:

      make

   5. Run the following command to install e2fsprogs:

      make install

4. Run the following command to check whether e2fsprogs is upgraded:

   rpm -qa | grep e2fsprogs

How do I disable the lazy init feature on a Linux instance?

By default, the lazy init feature of ext4 file systems is enabled. When the feature is enabled, the instance initiates a thread to continuously initialize the metadata of ext4 file systems. If you format a data disk when the feature is enabled, the IOPS of the disk may be temporarily affected.

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