Help Center/ Elastic Volume Service/ User Guide/ Changing the EVS Disk Type (OBT)
Updated on 2026-05-11 GMT+08:00
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Changing the EVS Disk Type (OBT)

Scenarios

As your services grow, the performance of your existing disks may no longer meet your service requirements. For example, data processing may slow down or response times may increase. At this point, improving disk performance becomes essential to support ongoing service growth. You can address this issue by changing to a disk type that offers higher 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.
  • If a disk has more than 128 snapshots, its disk type cannot be 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.
  • If a disk is protected by Business Recovery Service (BRS), its disk type cannot be changed.
  • If you plan to change the disk type from Ultra-high I/O to Extreme SSD, make sure the current disk capacity is at least 461 GiB. Otherwise, the performance may not improve as expected and could even deteriorate after the change.

During the change
  • When the disk type is being changed, some operations cannot be performed on the disk, such as 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 disk types is an unstoppable process that may take several seconds or even hours to complete. The duration depends on the throughput and storage space at the time of the change, as well as the original disk type. After the change starts, you can find the disk in the disk list and check the process.
  • In rare cases, the change may fail due to resource problems. In this case, you are advised to try again.
  • You can change the disk type of up to 10 disks 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 lists the supported disk type changes.

Supported disk type changes vary by region. You can view the allowed changes on the console.

Table 2 Supported disk type changes

Original Disk Type

New Disk Type

Extreme SSD V2

Extreme SSD V2 (IOPS changed)

General Purpose SSD V2

General Purpose SSD V2 (IOPS or throughput, or both changed), Ultra-high I/O, General Purpose SSD, or Extreme SSD

Extreme SSD

General Purpose SSD V2 (IOPS or throughput, or both changed), Ultra-high I/O or General Purpose SSD

Ultra-high I/O

General Purpose SSD V2 (IOPS or throughput, or both changed), Extreme SSD or General Purpose SSD

General Purpose SSD

General Purpose SSD V2 (IOPS or throughput, or both changed), Extreme SSD or Ultra-high I/O

High I/O

General Purpose SSD V2 (IOPS or throughput, or both changed), Extreme SSD, Ultra-high I/O, or General Purpose SSD

Common I/O (previous generation product)

General Purpose SSD V2 (IOPS or throughput, or both changed), Extreme SSD, Ultra-high I/O, General Purpose SSD, or High I/O

Impact on the System

During a disk specifications change, data read and write operations continue normally and services are not interrupted. However, the change may temporarily affect the disk performance. Therefore, you are advised to perform the change during off-peak hours to avoid any impact on service stability.

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 for 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 the new price based on your selection.

    To change to the General Purpose SSD V2 type, you also need to specify the disk IOPS or throughput or both.

    To change to the Extreme SSD V2 type, you also need to specify the disk IOPS.

  4. Click Submit.

    The disk list page is displayed. If the disk type changes to the target type, the change is successful.

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

Helpful Links

  • To learn more about the disk performance, see Disk Types and Performance.
  • After a disk type change, the performance of the disk is not only determined by the new disk type. It is also determined by the instance that the disk is attached to. For details, see Instance QoS.