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 cloud server 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 Cloud Server 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

Log in to the management console.
Under Storage, click Elastic Volume Service.
The disk list page is displayed.
Click Buy Disk.

Configure basic disk information according to Table 2.

**Table 2** Disk parameters
Parameter	Sub-Parameter	Description	Example Value
Billing Mode	-	Mandatory Pay-per-use	Pay-per-use
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
Disk Specifications	Disk Type	Mandatory The available disk types are as follows: High I/O General Purpose SSD Ultra-high I/O Extreme SSD NOTE: 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.	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
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. Confirm to create the agency on the displayed Create Agency dialog box. 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 Master Key: After the KMS access rights have been granted to EVS, the system automatically creates a Default Master Key and names it evs/default. An existing or new CMK. For details about how to create one, see Creating a CMK. 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.	-
More	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.	-
Enterprise Project	-	Mandatory When creating EVS disks, you can add the disks to an existing enterprise project. An enterprise project facilitates project-level management and grouping of cloud resources and users. The default project is default.	default
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	-	(Optional) The number of disks to be created. The default value is set to 1, which means only one disk is created. Currently, you can create up to 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.	1

Click Next.
1. On the Details page, check the disk information again.
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.
In the disk list, view the disk status.
When the disk status changes to Available, the disk is successfully created.