Help Center/ Elastic Volume Service/ User Guide/ Changing the EVS Disk Type (OBT)
Updated on 2025-09-19 GMT+08:00
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Changing the EVS Disk Type (OBT)

Scenarios

If the performance of an existing disk no longer meets your service requirements, you can change the disk type to improve the disk performance.

This function is in OBT. Submit a ticket to apply for OBT.

Constraints

Table 1 Constraints on the disk type change

Phase

Description

Before the change
  • You can only change the disk type when the disk status is Available or In-use.
  • The disk type cannot be changed when any snapshot of the disk is being deleted.
  • A disk having more than 128 snapshots cannot have its disk type changed. You can delete some snapshots and then perform the change.
  • In rare cases, the disk type may fail to be changed due to a background resource issue. If this happens, submit a service ticket.
  • A disk protected by SDRS cannot have its disk type changed.

During the change
  • Some operations cannot be performed on the disk. Such operations include creating snapshots, creating backups, expanding the disk capacity, rolling back data from a snapshot, restoring data from a backup, attaching or detaching the disk, deleting the disk, transferring the disk, and creating an image from the ECS.
  • Changing the disk type may take several hours or even longer, and cannot be stopped. The time depends on the throughput, storage space, and original disk type at the time of the change.
  • In rare cases, the change may fail due to resource problems. In this case, you are advised to perform the change again.
  • You can have a maximum of 10 disks with their types being changed at the same time.
  • The OS cannot be changed if you are changing the disk type of a system disk.

After the change

The following table shows the supported changes between disk types.

Supported changes between disk types vary depending on regions. See the allowed changes on the console.

Table 2 Supported changes between disk types

Source Disk Type

New Disk Type

Extreme SSD

Ultra-high I/O or General Purpose SSD

Ultra-high I/O

Extreme SSD or General Purpose SSD

General Purpose SSD

Extreme SSD or Ultra-high I/O

High I/O

Extreme SSD, Ultra-high I/O, or General Purpose SSD

Impact on the System

Read and write operations on the disk are not affected, but the disk performance may be affected. Perform the change during off-peak hours.

Billing

After a disk specifications change, the billing of the disk will also be changed:

  • For a pay-per-use disk, the disk will be billed based on the billing standards of the new disk type.
  • For a yearly/monthly disk, the disk expiration time remains unchanged, and the system will calculate the price difference based on the remaining days and the price difference between the original and new disk specifications.

Prerequisites

You are advised to create a snapshot for the disk to back up the disk data before changing the disk specifications. For details, see Creating an EVS Snapshot.

Procedure

  1. Sign in to the EVS console.
  2. In the disk list, locate the target disk, click More in the Operation column, and choose Modify Specifications.

    The Modify Specifications page is displayed.

  3. Select a disk type from the drop-down list. The system shows you the new price based on your selection.
  4. Click Submit.

    The disk list is displayed, and the disk status is Changing disk type, indicating that the disk type is being changed. After the disk type changes to the target type, the operation is successful.

    If the disk is a yearly/monthly disk, the costs may change. Handle resource change orders in a timely manner.