EVS Disk

Description

System disk
A system disk stores the OS of an ECS, and is automatically created and initialized once the ECS is created.

Data disk
A data disk stores user data.

You can buy a data disk when purchasing an ECS or after an ECS is purchased. If you buy a data disk when purchasing an ECS, the system will automatically attach the data disk to the ECS. If you purchase a data disk after an ECS is purchased, you need to manually attach the data disk.

After you attach a data disk to an ECS, you need to initialize the disk before using it.

Initializing EVS Data Disks

Disk types
There are six types of EVS disks classified by I/O performance: extreme SSD, general-purpose SSD V2, ultra-high I/O, general-purpose SSD, high I/O, and common I/O.
- Extreme SSD disks are ideal for applications that require ultra-large bandwidth and ultra-low latency.
- General-purpose SSD V2 disks are suitable for interactive workloads that demand high performance and low latency.
- Ultra-high I/O disks are excellent for enterprise mission-critical services as well as workloads demanding high throughput and low latency, such as ultra-high bandwidth read/write-intensive scenarios and I/O-intensive scenarios.
- General-purpose SSD disks are used for high-throughput and low-latency applications, such as enterprise office applications and large-scale development and testing.
- High I/O disks are ideal for common workload scenarios, such as common development and testing.
- Common I/O (previous-generation product) disks are used for infrequently accessed workloads.
EVS disks differ in performance and price. Choose the disk type most appropriate for your applications.

Disk Types and Performance
Device type
EVS device types are classified as Virtual Block Device (VBD) and Small Computer System Interface (SCSI) based on whether advanced SCSI commands are supported.

The default device type is VBD. If SCSI is selected, the disk will support transparent SCSI command transmission.

Device Types and Usage Instructions
Shared disk
Shared EVS disks are block storage devices that can be attached to multiple cloud servers and support concurrent reads/writes. These disks feature multiple attachments, high-concurrency, high-performance, and high-reliability. They are mainly used to provide cluster deployment and high availability (HA) capabilities required by certain applications. A shared EVS disk can be attached to a maximum of 16 ECSs.

Managing Shared EVS Disks
EVS disk encryption
EVS disk encryption safeguards your data security. Snapshots generated from encrypted disks and disks created using these snapshots automatically inherit the encryption function.

Managing Encrypted EVS Disks

To enable encryption, click Create Agency to assign KMS access permissions to EVS. If you can grant permissions, assign the KMS access permissions to EVS. If you cannot, contact the user having the Security Administrator permissions to do this.
- Agency Name: EVSAccessKMS: specifies that permissions have been assigned to EVS to obtain KMS keys for encrypting or decrypting EVS disks.
- KMS Key Name: specifies the name of the key used by the encrypted EVS disk. By default, the name is evs/default.
- KMS Key ID: specifies the ID of the key used by the encrypted data disk.

FAQs

What Should I Do If the Disk Space Is Insufficient?

If the capacity of an existing disk is insufficient, you can expand the disk capacity. Both the system disk and data disks can be expanded. Disk capacity can be expanded only.

How Can I Expand the Disk Capacity?

How Are EVS Disks Billed?

EVS disks are billed by disk capacity and duration on a yearly/monthly or pay-per-use basis after they are purchased.

EVS Disk Pricing Details

Why Cannot I Find the New Disk Attached to My ECS?

Because the newly attached disk has not been partitioned or initialized. A newly attached EVS disk does not have partitions and file systems by default. That is why it is unavailable in My Computer. To resolve this issue, manually initialize the disk.

Initializing EVS Data Disks