This topic describes how to create a partition of the Master Boot Record (MBR) format for a new data disk attached to an ECS instance that runs the Windows system. Then, it describes how to mount an NTFS file system onto the partition. You can create multiple partitions for a data disk based on your business needs.

Background information

The following section describes the risks of formatting a data disk:
  • Disk partitioning and formatting are high-risk operations. Proceed with caution. This topic describes how to format a new data disk. If you have stored data on the data disk, you must create a snapshot for the data disk to avoid data loss. For more information, see Create a snapshot.
  • You can only partition data disks that are attached to ECS instances. You cannot perform this operation on the system disk. If you forcibly use a third-party tool to partition the system disk, unknown risks such as system failure and data loss may occur. You are only allowed to expand partitions or add new partitions for the system disk that has been expanded. For more information, see Extend a Windows file system.


The following procedure only applies to data disks with a size of less than 2 TiB. For more information about instructions for data disks with a size of greater than 2 TiB, see Partition and format data disks larger than 2 TiB. In this example, a 20 GiB data disk is attached to an ECS instance that runs the Windows Server 2012 R2 64-bit operating system. A single Master Boot Record (MBR) partition is created for the data disk.

  1. Connect to the instance.
  2. On the Windows Server desktop, right-click the Start icon, and select Disk Management.
  3. Find the unformatted data disk (Disk 2 in this example), which is in the Offline state.
  4. Right-click the blank space in Disk 2, and select Online.
    After Disk 2 goes online, Disk 2 enters the Not Initialized state.
  5. Right-click the blank space in Disk 2, and select Initialize Disk.
  6. In the Initialize Disk dialog box, select Disk 2, and select either of the following partition formats:
    • Currently, MBR is most frequently used. This format only supports data disks less than 2 TiB and a maximum of four primary partitions. If you want to divide a disk into more than four partitions, you need to use a primary partition as an extended partition and create logical partitions in it.
    • GUID Partition Table (GPT) is a new partition format, which cannot be recognized by earlier versions of Windows. The data disk size that GPT supports is determined by the operating system and the file system. In Windows, GPT supports a maximum of 128 primary partitions.

    In this example, select MBR, and click OK.

  7. In the Disk Management window, right-click the Unallocated section of Disk 2, and then select New Simple Volume.
  8. In the New Simple Volume wizard, perform the following operations:
    1. Click Next.
    2. Specify the size of the simple volume. If you want to create only one primary partition, use the default value. Click Next.
    3. Select a drive letter. In this example, select F. Click Next.
    4. Specify the formatting settings, including file system, allocation unit size, and volume label. Confirm whether to enable Quick Formatting and File and Folder Compression. In this example, use the default settings. Click Next.
    5. Start creating a simple volume. When the information shown in the following figure appears in the wizard, a new simple volume is created. Click Finish to close the New Simple Volume wizard.


After Disk 2 is partitioned and formatted, its status is displayed in the Disk Management window.

In This PC, you can view a new drive named New Volume (F:). The data disk is ready for you to use.