Block storage type and how to use block storage _ ECS

Block storage is a block device product provided by Alibaba Cloud for ECS. It has the characteristics of high performance and low latency, supports random reading and writing, and meets the data storage requirements in most general business scenarios. You can format and establish a file system on ECS to use block storage just like you use a physical hard disk. This article describes the types of block storage and how to use it.

Block Storage Type

Alibaba Cloud provides a wealth of block storage products for your ECS, including cloud disks based on distributed storage architecture and local disk products based on the local hard disk of the physical machine.

Cloud Disk Type

Cloud disk is a block storage product at the block level provided by Alibaba Cloud for ECS. It uses the distributed three copies mechanism to provide 99.9999999% data reliability assurance for ECS instances.

Classification by use

Cloud Disk Type	explain
System disk	It is the startup disk of an ECS instance and is used to store system related data such as operating system and program files. It can only be created and released with ECS instances. explain By default, the system disk is enabled and released with the instance. When the ECS instance is released, the system disk is automatically released together. If it is closed and released with the instance, the system disk will be uninstalled and retained as a data disk when the instance is released.
Data disk	It is used to store user data, logs, other application programs and other non system related data. It can be created with the ECS instance, or it can be created separately and then attached to the ECS instance for use. You can release the data disk manually or with the instance. For more information, see Release Cloud Disk 。

Classification by performance

According to different cloud disk performance, it can be divided into ESSD AutoPL cloud disk ESSD PL-X cloud disk The ESSD cloud disk, the ESSD Entry cloud disk, and the previous generation cloud disk (SSD cloud disk, efficient cloud disk, and ordinary cloud disk). The comparison of cloud disk types is as follows:

Cloud Disk Type	characteristic	Application scenarios	charging
ESSD AutoPL cloud disk	Capacity and performance can be decoupled Supports preconfigured cloud disk performance Support performance burst	Scenarios applicable to the ESSD cloud disk Cloud disk capacity is fixed, and cloud disk performance requirements are high The business fluctuates greatly, and the peaks appear frequently, so it is necessary to deal with sudden business	Cloud disk capacity fee Pre configured performance fee (charge by volume after starting) Sudden performance fee (charge by volume after opening)
ESSD PL-X cloud disk (invited test) explain The ESSD PL-X cloud disk is in the process of being invited to test. The invited regions and zones only support the M-zone of East China 2 (Shanghai). To use, please go to Test invitation page apply.	Ultra high IOPS Ultra high throughput Ultra low delay Supports preconfigured cloud disk performance	OLTP database and KV database with higher requirements for cloud disk IOPS, throughput and delay	Cloud disk capacity fee Pre configured performance fee (enabled by default, charged after enabled)
ESSD cloud disk	High IOPS Low latency	Delay sensitive applications or I/O-intensive business scenarios: Large OLTP database NoSQL database Elasticsearch distributed log	Cloud disk capacity fee
ESSD Entry Cloud Disk explain only General force calculation type and Economical instance type family e Supports attaching the ESSD Entry cloud disk.	High IOPS Low latency	Development and test business As system disk	Cloud disk capacity fee

Previous generation cloud disk

SSD cloud disk, efficient cloud disk and ordinary cloud disk belong to the previous generation cloud disk products, and have gradually stopped selling in some regions and availability zones. When you select cloud disks, it is recommended to replace efficient cloud disks and ordinary cloud disks with ESSD PL0 cloud disks or ESSD Entry cloud disks, and replace SSD cloud disks with ESSD AutoPL cloud disks.

Cloud Disk Type	characteristic	Application scenarios	charging
SSD cloud disk	High random read/write performance high reliability	I/O-intensive applications Small and medium-sized relational databases and NoSQL databases	Cloud disk capacity fee
Efficient cloud disk	High cost performance high reliability	Development and test business As system disk	Cloud disk capacity fee
Ordinary cloud disk	High cost performance	Low cost, suitable for development and test business with low storage performance requirements	Cloud disk capacity fee

Local disk type

The local disk is the local hard disk device on the physical machine where the ECS instance is located. It provides local storage access for the ECS instance. The local disk is suitable for business scenarios that have very high requirements for storage I/O performance and mass storage cost performance. Alibaba Cloud provides the following two local disks:

type	Matching instance type	Application scenarios
NVMe SSD local disk	The following instance type families use NVMe SSD local disks together: Local SSD type i4, i4g, i4r, i3, i3g, i2, i2g, i2ne, i2gne, i1 GPU computing gn5	Taking the local SSD type instance type family as an example, the NVMe SSD local disk is applicable to the following scenarios: Online businesses such as online games, e-commerce, live video, media, etc. Meet the low latency and high I/O performance requirements of I/O-intensive applications for block storage. It has high requirements for storage I/O performance, and has a business scenario of application layer high availability architecture. For example, NoSQL non relational databases (such as Cassandra, MongoDB, HBase, etc.), MPP data warehouses, and distributed file systems.
SATA HDD local disk	The instance type families used together include big data type d3s, d2c, d2s, d1ne, and d1.	It is applicable to the Internet industry, financial industry and other industries with big data computing and storage analysis needs. It is a business scenario for massive data storage and offline computing. Fully meet the requirements of distributed computing business types represented by Hadoop on ECS instance storage performance, storage capacity and intranet bandwidth.

explain

This article mainly describes the information of local disks currently sold with ECS instances. For the performance details of the local SSD instance type and big data instance type, see Instance Type Family 。
For more information about local disks, see Local disk 。

Block storage performance

Different types of block storage have different performance:

Cloud Disk Performance Description: Cloud Disk Performance 。
Performance description of local disk: Local disk performance 。

data security

explain

Except for the data erasure mechanism, other contents are only applicable to cloud disks, not local disks.

Read write stability
In the same zone, your business data is distributed and stored in the block storage cluster in the form of multiple copies to ensure data stability during reading and writing, and achieve 99.9999999% data reliability assurance for ECS instances. For more information, see Cloud disk three copies technology 。
Proactive Backup
You can create snapshots regularly to improve the security of business data. Snapshots are Alibaba Cloud backup products that provide data backup capabilities for cloud disks and ensure that logs, customer transactions and other information can be backed up and queried. For more information, see Snapshot overview 。
Data erasure mechanism
The deleted data will not be accessed by other users through any way, and the deleted data in the distributed block storage system will be completely erased. The integrity of data erasure is mainly guaranteed through the following mechanisms:
- The bottom layer of cloud disk is based on sequential append write. This design takes full advantage of the high bandwidth and low latency characteristics of sequential write of physical disks. Based on the append write feature, the operation of deleting the logical space of the cloud disk will be recorded as metadata. The storage system will ensure that all read operations to the logical space return to zero. Similarly, your overwriting of logical space will not immediately overwrite the corresponding space on the physical disk. The storage system implements cloud disk overwriting by modifying the mapping relationship between logical space and physical space to ensure that the overwritten data cannot be read. All the legacy data on the physical disk formed by deletion or overwriting write operations will be permanently deleted from the underlying physical disk.
- When you release a block device (cloud disk), the storage system immediately destroys the metadata to ensure that the data can no longer be accessed. At the same time, the physical storage space corresponding to the cloud disk will be recycled. The physical space must be cleared before it is allocated again. Before the data is written for the first time, the read returns of all new cloud disks are all zero.
data encryption
For data sensitive applications, it is recommended that you encrypt the storage device. ECS cloud disk encryption uses the industry standard AES-256 algorithm, and uses the key to encrypt cloud disk and cloud disk snapshots. The data transferred from the ECS instance to the cloud disk will be automatically encrypted and automatically decrypted when reading data. For more information, see Overview of cloud disk encryption 。

Billing description

For the billing method and items of block storage, see Block storage charging 。

Restrictions on use

For block storage usage limits and quotas, see Block storage usage limit 。

Common operations of block storage

Common operations of cloud disk

In the whole use life cycle, the common operations of cloud disk are shown in the following figure.

Usage phase	scene	Operating Instructions
Creation phase	You can create an empty cloud disk or a cloud disk containing snapshot data for an ECS instance.	Create an empty cloud disk: Create cloud disk Attach data disk Initialize the data disk and create a file system: Initialize TiB data disks less than or equal to 2 (Linux) Initialize TiB data disks less than or equal to 2 (Windows) Initialize the TiB data disk larger than 2 Create a cloud disk containing backup data: Create a cloud disk using snapshots Attach data disk
Operation and maintenance stage	View basic cloud disk information and monitor cloud disk performance.	View Disk Serial Number View cloud disk monitoring information
	With the snapshot function, you can back up and restore cloud disk data.	Create a cloud disk snapshot Rollback cloud disk using snapshot
	If the performance of the existing cloud disk type is not enough, you can upgrade the configuration for the cloud disk.	Change cloud disk type Modify the ESSD cloud disk performance level Modify the ESSD AutoPL cloud disk performance configuration
	If the existing cloud disk storage capacity is insufficient, you can expand the cloud disk.	Step 1: Expand the cloud disk capacity Step 2: Expand the partition and file system Expanding partitions and file systems (Linux) Expand partitions and file systems (Windows)
	Encrypt the data stored on the cloud disk.	Encryption system disk Encrypted data disk
	If you need to restore the cloud disk to the state it was created in, you can reinitialize it.	Reinitialize the system disk Reinitialize the data disk
	If the system disk is damaged, you can uninstall the system disk, repair it, and then mount it back to the instance.	Uninstall or mount the system disk
	If you need to replace a new operating system, you can replace the operating system.	Replace the operating system (system disk)
Release phase	If you no longer need to use the cloud disk, you can uninstall and release the cloud disk to save costs.	Pay As You Go: Unload Data Disk Release Cloud Disk Annual/monthly subscription: Convert to pay as you go method: Convert cloud disk billing method Unload Data Disk Release Cloud Disk

Common Operation of Local Disk

The local disk can only be created and released with ECS instances of some instance types. For more information, see Local disk 。

Overview of Block Storage