Help Center> Elastic Volume Service> Getting Started> Step 2: Purchase an EVS Disk
Updated on 2023-08-25 GMT+08:00

Step 2: Purchase an EVS Disk

Scenarios

EVS disks can be used as system disks or data disks for servers. You can purchase data disks on the EVS console, or purchase them together with system disks on the ECS console.

This section describes how to purchase data disks on the EVS console.

Constraints

Table 1 Constraints on purchasing disks

Purchased On

Description

The EVS console

  • Disks purchased on the EVS console are data disks. You need to manually attach them to servers.
  • Disks can only be attached to servers in the same region and AZ. Once purchased, the region and AZ cannot be changed.
  • Yearly/Monthly disks can be purchased on the EVS console only when you have selected to attach them to a yearly/monthly server.
  • There are quantity and capacity quotas on EVS disks, so properly plan the number of disks and total disk capacity your workloads require. For details, see Managing Quotas.

The ECS console

  • System disks can only be purchased together with servers and are automatically attached.
  • Data disks purchased together with servers or added after the server purchase are automatically attached.
  • Disks will have the same billing mode as their server if the disks are purchased together with the server.
  • By default, disks purchased with ECSs are VBD disks, and those purchased with BMSs are SCSI disks.

-

Capacities of multiple disks cannot be combined, and the capacity of a single disk cannot be split.

Procedure

  1. Go to the Buy Disk page.
  2. Configure basic disk information according to Table 2.

    Table 2 Disk parameters

    Parameter

    Sub-Parameter

    Description

    Example Value

    Region

    -

    Mandatory

    Resources are region-specific and cannot be used across regions through internal network connections. For low network latency and quick resource access, select the nearest region.

    -

    AZ

    -

    Mandatory

    The availability zone (AZ) where you want to create the disk.

    NOTE:
    • Disks can only be attached to the servers in the same AZ.
    • The AZ of a disk cannot be changed after the disk has been created.

    AZ1

    Attach To Server (Optional)

    -

    Optional

    If you want to purchase yearly/monthly disks, this parameter is mandatory.

    After the disks are attached, you still need to log in to the server and initialize the disks before they can be used.

    NOTE:

    This parameter is available only in some regions. Whether it is displayed depends on the region where you use EVS.

    -

    Billing Mode

    -

    Mandatory

    You can pay for EVS disks in two ways:

    • Yearly/Monthly
    • Pay-per-use
      NOTICE:
      • If you have selected a server to attach the disk, both yearly/monthly and pay-per-use billing modes are available.
      • If you choose not to attach the disk, only pay-per-use billing is available.

    Pay-per-use

    Disk Specifications

    Disk Type

    Mandatory

    The available disk types are as follows:

    • Common I/O (previous generation product)
    • High I/O
    • General Purpose SSD
    • Ultra-high I/O
    • General Purpose SSD V2
    • Extreme SSD
    NOTE:

    General Purpose SSD V2 disks allow you to specify the disk IOPS and throughput. See the supported performance ranges in Disk Types and Performance.

    When a disk is created from a snapshot, the disk type of the new disk will be consistent with that of the snapshot's source disk.

    The disk type can be changed after the disk is purchased. The new disk type must have a higher specification. For example, high I/O can only be changed to ultra-high I/O, but cannot be changed to common I/O.

    Ultra-high I/O

    Disk Size (GiB)

    Mandatory

    The disk size. Only data disks can be created on the current page, and the disk size ranges from 10 GiB to 32,768 GiB.

    NOTE:
    • When you use a backup to create a disk, the disk capacity must be greater than or equal to the backup size. In the condition that you do not specify the disk capacity, if the backup size is smaller than 10 GiB, the default capacity 10 GiB will be used as the disk capacity; if the backup size is greater than 10 GiB, the disk capacity will be consistent with the backup size.
    • When you use a snapshot to create a disk, the disk capacity must be greater than or equal to the snapshot size. In the condition that you do not specify a disk capacity, if the snapshot size is smaller than 10 GiB, the default 10 GiB will be used as the disk capacity; if the snapshot size is greater than 10 GiB, the disk capacity will be consistent with the snapshot size.
    • The system shows you the maximum number of disks as well as the maximum disk capacity allowed to purchase. To ensure effective resource usage, if the disk capacity you need exceeds the upper limit, click Increase Quota to obtain a higher quota. You can purchase the disk capacity you need after the request is approved.

    100 GiB

    Create from
    • Backup
    • Snapshot
    • Image
    Optional
    • If you choose Create from Backup, the backup data is used to create the disk.

      Click Create from and choose Backup. On the displayed page, select the target backup and click OK.

      NOTE:
      • One backup cannot be used for concurrent disk creation operations at the same time. For example, if you are creating disk A from a backup, this backup can be used to create another disk only after disk A has been created.
      • If a disk is created from a backup of a system disk, the new disk can be used as a data disk only.
    • If you choose Create from Snapshot, the snapshot data is used to create the disk.

      Click Create from and choose Snapshot. On the displayed page, select the target snapshot and click OK.

      NOTE:
      • The device type of the new disk is the same as that of the snapshot's source disk.
      • The encryption attribute of the new disk is the same as that of the snapshot's source disk.
    • If you choose Create from Image, the image data is used to create the disk.

      Click Create from and choose Image. On the displayed page, select the target image and click OK.

      NOTE:
      • The device type of the new disk is the same as that of the image's source disk.
      • The encryption attribute of the new disk is the same as that of the image's source disk.
    • Create from Backup: autobackup-001

    Automatic Backup

    -

    CBR lets you back up EVS disks and ECSs and use the backups to restore data. After you configure automatic backup, the system will associate the EVS disk with the backup vault and apply the selected policy to the vault to periodically back up the disk.
    • Do not use: Skip this configuration if backup is not required. If you need backup protection after a disk has been purchased, log in to the CBR console, locate the desired vault, and associate the disk with the vault.
    • Use existing:
      1. Select an existing cloud backup vault from the drop-down list.
      2. Select a backup policy from the drop-down list, or log in to the CBR console and configure a desired one.
    • Buy new:
      1. Set the name of the cloud backup vault, which can contain a maximum of 64 characters, including letters, digits, underscores (_), and hyphens (-), for example, vault-f61e. The default naming rule is vault_xxxx.
      2. Enter the vault capacity, which is required for backing up the disk. The vault capacity cannot be less than the size of the disk to be backed up. The value ranges from the disk size to 10,485,760 in the unit of GiB.
      3. Select a backup policy from the drop-down list, or log in to the CBR console and configure a desired one.

    -

    More

    Advanced Settings
    • Share
    • SCSI
    • Encryption

    Optional

    • Share

      If you select Share, a shared disk is created. A shared disk can be attached to up to 16 servers. If you do not select Share, a non-shared disk is created, and the disk can be attached to one a server only.

      If you select both SCSI and Share, a shared SCSI disk is created.

      NOTE:

      The sharing attribute of a disk cannot be changed after the disk has been created.

    • SCSI

      If you select SCSI, a SCSI disk is created. Such disks allow the server OS to directly access the underlying storage media and send SCSI commands to the disks. If you do not select SCSI, a VBD disk is created. That said, the disk device type is VBD, the default device type.

      NOTE:

      The device type of a disk cannot be changed after the disk has been created.

    • Encryption

      The encryption function on this console is used for data disk encryption only.

      System disk encryption relies on the image. For details, see Creating Encrypted Images.

      To use the disk encryption function, select Encryption. Then configure the encryption parameters as prompted:
      • Create Agency

        An agency is a trust relationship between two tenants or services. A tenant can create an agency to grant resource access rights to another tenant or service. If the KMS access rights are not granted to EVS, the Create Agency dialog box will be displayed. Otherwise, it will not be displayed.

        Click Yes to grant the KMS access rights to EVS. After the rights have been granted, EVS can obtain KMS keys to encrypt or decrypt EVS disks.

        After the KMS access rights have been granted, follow-up operations do not require the rights to be granted again.

      • KMS Key Name

        KMS Key Name is displayed only after the KMS access rights have been granted.

        KMS Key Name is the identifier of the key, and you can use KMS Key Name to specify the KMS key that is to be used for encryption. One of the following keys can be used:

        Default Key: After the KMS access rights have been granted to EVS, the system automatically creates a Default Key evs/default.

        An existing or new custom key. For details about how to create one, see Creating a Custom Key.

      NOTE:
      • Before you use the encryption function, KMS access rights need to be granted to EVS. If you have the right to grant the permission, grant the KMS access rights to EVS directly. If you do not have this permission, contact a user with the security administrator rights to grant KMS access rights to EVS, then repeat the preceding operations.
      • The encryption attribute of a disk cannot be changed after the disk has been created.

    -

    Tag

    Optional

    During the EVS disk creation, you can tag the EVS resources. Tags identify cloud resources for purposes of easy categorization and quick search.

    A tag is composed of a key-value pair.
    • Key: Mandatory if the disk is going to be tagged

      A tag key can contain a maximum of 36 characters. It consists of letters, digits, underscores (_), hyphens (-), and Unicode characters (\u4E00-\u9FFF).

    • Value: Optional if the disk is going to be tagged

      A tag value can contain a maximum of 43 characters. It consists of letters, digits, underscores (_), periods (.), hyphens (-), and Unicode characters (\u4E00-\u9FFF).

    NOTE:
    • A maximum of 10 tags can be added for an EVS disk.
    • Tag keys of the same EVS disk must be unique.

    For details about tags, see the Tag Management Service User Guide.

    -

    Disk Name

    -

    Mandatory

    • If you create disks individually, this parameter value is used as the actual disk name.

      The name can contain a maximum of 64 characters.

    • If you create disks in a batch, this parameter value is used as the prefix of disk names, and one disk name will be composed of this parameter value and a four-digit number.

      The name can contain a maximum of 59 characters.

    For example, if you create two disks and set volume for Disk Name, the EVS disk names will be volume-0001 and volume-0002.

    Quantity

    -

    • Usage duration: This parameter is mandatory if you select Yearly/Monthly for Billing Mode.

      You can choose 1 month to 3 years for the usage duration.

    • Disk quantity: This parameter is optional.

      The default value is set to 1, which means one disk will be created. You can create a maximum of 100 disks at a time.

    NOTE:
    • If the disk is created from a backup, batch creation is not possible, and this parameter must be set to 1.
    • If the disk is created from a snapshot, batch creation is not possible, and this parameter must be set to 1.
    • The system shows you the maximum number of disks as well as the maximum disk capacity allowed to purchase. To ensure effective resource usage, if the number of disks you need exceeds the upper limit, click Increase Quota to obtain a higher quota. You can purchase the disks you need after the request is approved.

    Disk validity period: 1 year

    Disk quantity: 1

  3. Click Next.

    • If you select Yearly/Monthly for Billing Mode:
      1. Check the disk details on the Confirm page.
      2. Confirm the information and click Submit.
      3. On the Pay page, select a desired payment method and confirm the payment. The system displays a message indicating payment processed successfully.
      4. Click Back to Elastic Volume Service to return to the Elastic Volume Service page.
    • If you select Pay-per-use for Billing Mode:
      1. Check the disk details on the Confirm page.
      2. Confirm the information and click Submit. The system displays a message indicating request submitted successfully.
      3. Click Back to Disk List to return to the Elastic Volume Service page.

  4. Click Back to Disk List. The disk list page is displayed.
  5. In the disk list, view the disk status.

    When the disk status changes to Available, the disk is successfully created.