Elastic Compute Service:Resize a disk (Windows)

Prerequisites

Ensure one of the following conditions is met:

• The disk is attached to a non-expired ECS instance that is in the Running or Stopped state.

• The disk status is Unattached (Available).

Procedure

1. Go to ECS console - Block Storage. In the top navigation bar, select the target region and resource group.

2. In the Actions column for the target disk, click Resize.

3. Create a snapshot to back up the disk data. This prevents data loss from incorrect operations during the expansion process. On the Determine Disk and Read Notes page, verify the information and click Create Snapshots. Set a name and retention period for the snapshot, and then click OK.

   Important

   Using snapshots incurs fees.

   

4. You cannot resize the disk while a snapshot is being created. After the snapshot is created, refresh the page. When the Resizing Supported column displays Yes, click I Understand Risks and Have Backed Up Data. Proceed.

   The time required to create a snapshot is affected by factors such as data volume and bandwidth. Go to the Snapshots page in the ECS console to view the progress in the Progress column for the target snapshot.

5. On the Configure Resizing Method And New Size page, set the expansion parameters, confirm the fee, and click OK.

   Important

   You are charged for the added capacity when you resize a disk.

   Parameter	Description
   New Disk Size	The capacity after expansion cannot be smaller than the current capacity.
   Resizing Method	Online Resizing (Recommended): After you increase the capacity, you do not need to restart the instance. The new capacity takes effect immediately. Offline Resizing: The disk is in the Unattached state, the instance is in the Stopped state, or some instance types support only offline expansion.

6. (Conditionally required) If the disk is a subscription disk, wait for the 5-second countdown in the payment dialog box to finish. Click Complete Payment. After completing the payment, return to the expansion flow and click Paid. Close the dialog box.

   If you click Paid but do not complete the payment, resizing will be blocked. To proceed, click Go to Order Center in the Actions column, complete the payment, and then return to the resizing process.

7. On the Confirm Resizing Results page, after the Disk Resize Completed column displays Successful, you must extend partitions and file systems to use the new capacity.

Prerequisites

• If the disk is in the Unattached (Available) state, attach it to an ECS instance.

• If you performed offline resizing for a disk attached to an instance, restart or start the instance first.

• For unformatted data disks (no file system), refer to Initialize a data disk to complete the operation.

Procedure

This procedure uses Windows Server 2022 as an example.

1. Determine whether to convert the partition.

   1. Go to ECS console - Instance. In the top navigation bar, select the target region and resource group.

   2. Go to the details page of the target instance. Click Connect and select Workbench. Set the connection method to Terminal and enter your username and password to log on to the graphical terminal.

   3. On the Windows Server desktop, right-click the icon and select Disk Management.

   4. In the Disk Management window, right-click the target disk and select Properties from the pop-up menu.

   5. In the dialog box, click the Volumes tab and check the Partition style.

      If the partition style is Master Boot Record (MBR) and the capacity after resizing is greater than 2 TiB, refer to Convert the partition style of a data disk to GPT and re-partition the disk to complete the resizing.

2. Extend partitions and file systems.

   Use the increased capacity to extend an existing partition

   1. In the Disk Management dialog box, select Action > Rescan Disks to view the unallocated disk capacity.

   2. Right-click the last partition on the disk and select Extend Volume.

      Because disk partitions and file systems are independent, you can only extend the last partition on a disk. In the example, the unallocated space on Disk 1 can only be added to New Volume (E:).

      

   3. Follow the default settings in the Extend Volume Wizard. After the extension, the new capacity is automatically added to the last partition. Check that the disk data and your applications are working correctly.

   Use the increased capacity to create a new partition

   1. In the Disk Management dialog box, choose Action > Rescan Disks to view the unallocated disk capacity.

   2. Right-click the unallocated space and select New Simple Volume.

   3. In the New Simple Volume Wizard, accept the default settings to complete the operation.

FAQ about resizing disks

• Why is the I Understand Risks and Have Backed Up Data. Proceed button grayed out?

  This happens if a snapshot is being created for the disk. Wait for the snapshot creation process to complete before resizing.

• I performed an offline resizing but do not want to restart the instance. What can I do?

  An offline resizing requires an instance restart to take effect. If your business does not allow a restart, you can perform a small online resize (such as 1 GiB). This action will force both the original offline resize and the new online resize to take effect immediately without a restart. This is a secondary resizing and incurs additional fees. Proceed with caution.

• Instance types that support only offline resizing

  • ecs.ebmc4.8xlarge

  • ecs.ebmhfg5.2xlarge

  • ecs.ebmg5.24xlarge

  • ecs.t1

  • ecs.s1

  • ecs.s2

  • ecs.s3

  • ecs.c1

  • ecs.c2

  • ecs.m1

  • ecs.m2

• How do I resize a disk using the API?

  1. (Recommended) Back up data: Before resizing, call the CreateSnapshot operation to create a snapshot.

     Using snapshots incurs snapshot fees.

     Important

     Back up your data in advance to prevent data loss from incorrect operations during the resizing.

  2. After the snapshot is created, call the ResizeDisk operation to increase the disk capacity.

  3. After resizing, you must also extend partitions and file systems.

     • Call the RunCommand operation to send commands to the target instance.

     • Call the DescribeInvocations operation to query the command output.

     Commands

     1. Check whether the partition type needs to be converted.

        Get-Disk 

        Response Parameter	Description
        Number	The ordinal number of the disk.
        Partition Style	The partition format of the disk.

        If the Partition Style is MBR and the capacity after resizing is greater than 2 TiB, refer to Convert the partition style to GPT and re-partition the disk to complete the resizing.

     2. Extend partitions and file systems.

        Use the increased capacity to extend an existing partition

        1. Determine the drive letter of the disk to extend. <Number> is the disk ordinal number that you obtained in the previous step.

           Get-Partition -DiskNumber <Number>

           In the response, DriveLetter is the drive letter of the partition to extend. If there are multiple partitions, you can only extend the last one.

        2. Extend the partition and file system. <DriveLetter> is the drive letter that you obtained in the previous step.

           Resize-Partition -DriveLetter <DriveLetter> -Size (Get-PartitionSupportedSize -DriveLetter <DriveLetter>).sizeMax

        3. Check the result of the partition and file system extension.

           Run Get-Partition -DiskNumber <Number> and check the Size field. If the partition size is as expected, the extension is successful.

        Use the increased capacity to create a new partition

        1. Check the partition status of the disk to extend. <Number> is the disk ordinal number that you got in the previous step.

           Get-Partition -DiskNumber <Number>

           In the response, DriveLetter is the drive letter of the existing partition.

        2. Create a new partition.

           Command Parameter	Description
           -DiskNumber	Specifies the disk ordinal number. Replace <Number> with the disk ordinal number that you obtained in the first step.
           -UseMaximumSize	Indicates that the command uses the maximum available capacity.
           -DriveLetter	Replace <DriveLetter> with the drive letter for the new partition. It cannot be the same as the drive letter of the existing partition.

           New-Partition -DiskNumber <Number> -UseMaximumSize -DriveLetter <DriveLetter>

        3. Initialize the new partition.

           Command Parameter	Description
           -DriveLetter	Replace <DriveLetter> with the drive letter that you set in the previous step.
           -FileSystem	Replace <FileSystem> with the file system type, such as NTFS.
           -Confirm:$false	Skips the confirmation prompt.

           Format-Volume -DriveLetter <DriveLetter> -FileSystem <FileSystem> -Confirm:$false

        4. View information about the new partition.

           Run Get-Partition -DiskNumber <Number> to view basic information about the new partition.

FAQ about extending partitions and file systems

• Unallocated space is not detected after I rescan for disks.

  For instances created before March 30, 2019, the virtio driver version may be earlier than 58011. You must restart the instance to detect the new space. You can run the following command in PowerShell to check the driver version. If necessary, you can update the virtio driver for a Windows instance.

  [System.Diagnostics.FileVersionInfo]::GetVersionInfo("C:\Windows\System32\drivers\viostor.sys")

• Can the capacity of a data disk be used to extend another data disk or the system disk?

  Because disk partitions and file systems are independent, you can only extend the last partition on the same disk. You cannot allocate the capacity to other disks. Therefore, the capacity of a data disk cannot be used to extend another data disk or the system disk.

• I receive the error message: "The volume cannot be extended because the number of clusters will exceed the maximum number of clusters supported by the file system."

  Cause: The Allocation unit size was set incorrectly when you initialized the disk. For more information about disk capacity limits, see NTFS overview.

  Allocation Unit Size:

  • To extend to a capacity from 16 TiB to 32 TiB (inclusive), make sure the allocation unit size was set to 8192 during initialization.

  • To extend to a capacity from 32 TiB to 64 TiB (inclusive), make sure the allocation unit size was set to 16K during initialization.

  Solution:

  Important

  The Allocation unit size is set when the disk is initialized and cannot be changed afterward.

  1. Check the Allocation unit size of the disk that you want to resize.

     Log on to the instance, open the PowerShell command-line interface, and run the following command to retrieve the Allocation unit size. The following example shows how to check drive D:

     The Bytes Per Cluster in the output is the Allocation unit size.

     fsutil fsinfo ntfsinfo D:

  2. Choose a solution based on your requirements.

     Create a new disk and copy data

     1. Create an empty data disk with the target capacity for the current instance.

     2. Select the correct allocation unit size when you initialize the data disk.

     3. Manually copy the data from the original disk to the new disk.

     4. Verify that your services are restored. After the operation is complete, restart the relevant services and check that they are running correctly.

     5. After you confirm that your services are running correctly, you can detach the original data disk and release it. For more information, see Detach a data disk and Release a disk.

     Use the increased capacity to create a new partition

     1. In the Disk Management dialog box, choose Action > Rescan Disks to view the unallocated disk capacity.

     2. Right-click the unallocated space and select New Simple Volume.

     3. In the New Simple Volume Wizard, accept the default settings to complete the operation.

• API commands to convert the partition style and re-partition the disk

  Important

  During the conversion, the disk data is unavailable, which may affect your services. Plan a downtime window. Stop your services first. After the conversion is complete and the data is restored, you can resume your services.

  Step 1: Convert the partition format and re-partition the disk

  • During partition conversion in Windows, you must delete the volume. Deleting a volume clears all data on it. Before you convert the partition, call the CreateSnapshot operation to create a snapshot to back up the disk data. After the partition is converted, you must restore the data from the snapshot.

  • Call the RunCommand operation to send commands to the target instance.

  • Call the DescribeInvocations operation to query the command output.

  Commands

  1. Convert the partition format

     1. Get the ordinal number (Number) and total capacity (Total Size) of the target disk.

        Get-Disk 

     2. Determine the partition number (PartitionNumber) of the target disk. <Number> is the disk ordinal number that you got in the previous step.

        Get-Partition -DiskNumber <Number>

     3. Delete the partition on the target disk.

        Important

        The Delete Volume operation permanently erases all data from the volume. Before you delete the volume, call the CreateSnapshot operation to create a backup snapshot.

        Command Parameter	Description
        -DiskNumber	<Number> is the disk ordinal number that you obtained in the first step.
        -PartitionNumber	<PartitionNumber> is the partition number that you obtained in the previous step.
        -Confirm:$false	Skips the confirmation prompt.

        Remove-Partition -DiskNumber <Number> -PartitionNumber <PartitionNumber> -Confirm:$false

     4. After you delete all partitions on the target disk, convert the partition style.

        1. Enter the diskpart tool.

           diskpart

        2. List information about all disks.

           list disk

        3. Select the disk to convert.

           <Number> is the disk ordinal number that you got in the first step.

           select disk <Number>

        4. Run the following command to convert the partition type to GPT.

           convert gpt

        5. Run the following command to exit the diskpart tool.

           exit

     5. Check whether the conversion is successful.

        Run the Get-Disk command. If the Partition Style of the destination disk is GPT, the partition type was successfully converted.

  2. Repartition the disk

     1. Run the following command to repartition the disk.

        Command Parameter	Description
        -DiskNumber	<Number> is the disk ordinal number that you obtained in Step 1.
        -Size	<Size> is the custom size of the new partition, such as 40 GB.
        -DriveLetter	<DriveLetter> is the custom drive letter of the new partition.
        -FileSystem	<FileSystem> is the file system type of the new partition, such as NTFS.

        New-Partition -DiskNumber <Number> -Size <Size> -DriveLetter <DriveLetter> | Format-Volume -FileSystem <FileSystem>

     2. Run the Get-Partition -DiskNumber <Number> command to view information about the new partition.

  Step 2: Recover disk data

  • Call the CreateDisk API operation to create a data disk from the snapshot.

  • Call the AttachDisk API operation to attach the created data disk to the ECS instance to copy data. Do not roll back the snapshot. Otherwise, the disk may be reverted to the MBR format.