Help Center/ Elastic Cloud Server/ User Guide/ Instances/ Modifying ECS Specifications (vCPUs and Memory)/ Changing a KVM ECS to a QingTian ECS (Linux)
Updated on 2025-09-08 GMT+08:00
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Changing a KVM ECS to a QingTian ECS (Linux)

Scenarios

This section describes how to change a KVM ECS that runs Linux to a QingTian ECS.

Constraints

  • The ECS needs to be stopped during the specification modification, so you are advised to perform this operation during off-peak hours.
  • The network type cannot be changed during the specifications modification.
  • If a Linux ECS uses LVM logical disks consisting of physical volumes or uses RAID arrays as the system or data disk, the ECS specifications cannot be modified to prevent data loss.
  • QingTian ECSs can only have SCSI disks attached, and the disks will use WWN identifiers.
  • A KVM ECS can be changed to a QingTian ECS, but a QingTian ECS cannot be changed to a KVM ECS.
  • A Xen ECS cannot be changed to a QingTian ECS.
  • In the ECS OS, if the Logical Volume Manager (LVM) has the system.devices file feature enabled, a specification change may cause LVM to fail to match the disks based on the system.devices file. As a result, the LVM cannot identify disks.

    The system.devices file feature is enabled by default in Red Hat Enterprise Linux 9-based OSs, such as CentOS 9.x and Rocky Linux 9.x. Before modifying specifications for ECSs running any of these OSs, rename or remove system.devices in /etc/lvm/device.

    For details, see Limiting LVM device visibility and usage.

Procedure

Figure 1 shows the flowchart for changing a KVM ECS to a QingTian ECS.

Figure 1 Flowchart for changing a Linux ECS from KVM to QingTian
Table 1 Procedure for changing a KVM ECS to a QingTian ECS

Step

Description

1

Step 1: Back Up an ECS

2

Step 2: Execute the Specifications Modification Optimization Script

3

Step 3: Modify Specifications

4

(Optional) Step 4: Check Disk Attachment

Step 1: Back Up an ECS

If you modify the specifications of an ECS without installing the driver, the ECS may become unavailable and the data on the system disk may be lost. You are advised to back up the ECS first to prevent data loss.

  1. Check the ECS.

    Before backing up the ECS, stop and then start the ECS to ensure that services can run properly after the ECS is started.

  2. Back up the ECS.
    Backing up ECSs generate storage costs. There are two types of EVS snapshots: standard snapshots and legacy snapshots. Legacy snapshots are in OBT and free of charge. Standard snapshots are billed. Select the one type as required.
    • Method 1: Create a backup for the ECS.

      For details, see ECS Backup Procedure.

    • Method 2: Create a system disk snapshot and a data disk snapshot.

      For details about how to create a snapshot, see Creating an EVS Snapshot in Elastic Volume Service User Guide.

Backups and snapshots created for the ECS are used to restore data. If the specifications fail to be modified, you can use the backups or snapshots to restore data.

After the specifications are modified, if services are running properly, delete the ECS backups or snapshots from the corresponding service console.

Step 2: Execute the Specifications Modification Optimization Script

  1. Remotely log in to the ECS.
  2. Download the script to the root directory.

    curl URL > ~/offload_check_blockdevice.sh

    The URL is the address for downloading the specifications modification optimization script:

    Download address:

    If an abnormal output is returned, check whether the server has an EIP bound. In other regions, the script can be obtained only after the EIP is bound.

  3. Execute the specifications modification optimization script. The script automatically checks whether the ECS can be changed to a QingTian ECS.

    bash offload_check_blockdevice.sh

    Figure 2 Executing the script

    Wait until the script is executed. If the message "fstab file looks fine" is displayed, the script is executed successfully, and the KVM ECS can be changed to a QingTian ECS.

    Make sure that the ECS has been configured successfully, or the ECS may become unavailable after the specifications are modified.

Step 3: Modify Specifications

  1. Log in to the management console.
  2. Click . Under Compute, click Elastic Cloud Server.
  3. On the Elastic Cloud Server page, view the status of the target ECS.

    If the ECS is not in Stopped state, choose More > Stop in the Operation column.

  4. Choose More > Modify Specifications in the Operation column.

    The Modify ECS Specifications page is displayed.

  5. Select the new ECS type, vCPUs, and memory.
  6. (Optional) Set DeH.

    If the ECS is created on a DeH, you can change the DeH where the ECS resides.

    To do so, select the target DeH from the drop-down list. If no DeH is available in the drop-down list, it indicates that DeH resources are insufficient and cannot be used to create the ECS with new specifications.

  7. Select the checkbox to confirm that the configuration is complete.
  8. Click Next.
  9. Confirm the new specifications, read and agree to the agreement, and then click Submit Application.
    • The cloud platform automatically creates a system disk snapshot for you. After the specifications are modified, manually delete the snapshot on the snapshot page if you have verified that services are running properly.
    • If ECS specifications failed to be modified and the ECS becomes unavailable, reinstall the OS. This operation will clear the data on the system disk while the data on data disks is retained.

(Optional) Step 4: Check Disk Attachment

After a KVM ECS is changed to a QingTian ECS, disk attachment may fail. Therefore, check disk attachment after the ECS specifications are modified. If disks are properly attached, the specifications modification is successful.

Follow-up Procedure

If the ECS specifications have been modified but the OS cannot be started after remote login, contact customer service or reinstall the ECS OS to resolve this issue. For details, see Reinstalling the OS.

Reinstalling the OS will clear the system disk data, but the data on data disks is not affected.

After the specifications are modified, manually delete the snapshot on the snapshot page if you have verified that services are running properly.

Parent Topic: Modifying ECS Specifications (vCPUs and Memory)