Updated on 2024-04-18 GMT+08:00

General Operations


If ECS specifications do not meet service requirements, you can modify the ECS specifications, including vCPUs and memory. Certain ECSs allow you to change their types when you modify their specifications.

  • ECSs can be classified as the following based on the virtualization types:
    • Xen ECSs: S1, C1, C2, and M1 ECSs.
    • KVM ECSs: See the Virtualization column in ECS Specifications.


  • When modifying the specifications of an ECS, sold-out vCPU and memory resources are unavailable for selection.
  • Downgrading ECS specifications (vCPU or memory) will reduce performance.
  • Certain ECS types do not support specifications modification currently. For details about available ECS types and functions, see ECS Types. For details about restrictions on using different types of ECSs, see their notes.
  • When the disk status is Expanding, you are not allowed to modify the specifications of the ECS where the disk is attached.
  • Before modifying the specifications of a Windows ECS, modify the SAN policy by following the instructions provided in Why Does a Disk Attached to a Windows ECS Go Offline? to prevent disks from going offline after the specifications are modified.
  • For yearly/monthly ECSs that use paid images, the instance specifications cannot be downgraded, which means you cannot change the specifications to lower-cost ones.

Fees Description

Modifying specifications will lead to fee changes. For details, see Pricing of a Changed Specification.


After ECS specifications are modified, NIC flapping may occur. Before modifying the specifications, perform the following operations:

NIC flapping occurs because NIC retaining is enabled in the image from which the ECS is created.

For more information about NIC flapping, see What Should I Do If NIC Flapping Occurs After My ECS Specifications Are Modified?

  • Linux

    Run the following commands on the ECS to delete the files with persistent and net included in their names in the network rule directory:

    rm -fr /etc/udev/rules.d/*net*persistent*.rules

    rm -fr /etc/udev/rules.d/*persistent*net*.rules

  • Windows

    Delete the following directories in the registry on the ECS:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Profiles

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Signatures\Unmanaged

    Figure 1 Registry

Step 1: Modify Specifications

  1. Log in to the management console.
  2. Click in the upper left corner and select your region and project.
  3. Click . Under Compute, click Elastic Cloud Server.
  4. Click More in the Operation column and select Modify Specifications.

    The Modify ECS Specifications page is displayed.

  5. Select the new ECS type, vCPUs, and memory as prompted.

    Before modifying the specifications, stop the ECS or select Automatically stop the ECSs and then modify specifications.

    Figure 2 Modifying specifications
  6. Click Next.
  7. Confirm the settings, read and select the disclaimer, and then click Submit Application.
  8. Check whether the specifications have been modified.

    After modifying the specifications, you can check whether the specifications have been modified in Failures.

    1. Check whether Failures is displayed on the management console. For details, see Viewing Failed Tasks.
      • If yes, go to step 8.b.
      • If no, the specifications have been modified.
    2. Click Failures. Then, in the Failures dialog box, click Operation Failures and check whether the task is contained in the list by Name/ID, Operated At, or Task.
      • If yes, the specifications modification failed. See Follow-up Procedure for failure causes.
      • If no, the specifications have been modified.

Step 2: Check Disk Attachment

After specifications are modified, disk attachment may fail. Therefore, check disk attachment after specifications modification. If disks are properly attached, the specifications modification is successful.

Follow-up Procedure

Perform the following operations in the event of a specifications modification failure:

  1. Log in to the management console.
  2. Under Management & Governance, choose Cloud Trace Service.
  3. In the navigation pane on the left, choose Trace List.
  4. In the Trace Name column, locate the resizeServer event by resource ID.

    The resource ID is the ID of the ECS on which the specifications modification failed.

  5. Click View Trace in the Operation column to view the failure cause.

    If the fault cannot be rectified based on logs, contact customer service.