Block Storage is Alibaba Cloud's high-performance, low-latency block storage service for Elastic Compute Service (ECS). It supports random read/write operations for diverse workloads. With block storage devices, you can format and deploy file systems on ECS instances as you would use physical hard drives. This topic helps you get started with Block Storage by comparing the block storage devices it offers.
Categories of block storage devices
Alibaba Cloud's block storage devices fall into three main categories: cloud disks, built on a distributed storage architecture; local disks, directly attached to the host physical machine; and elastic ephemeral disks, providing transient storage tied to the instance lifecycle.
Cloud disks
Cloud disks are block-level data storage devices that use a distributed triplicate mechanism to achieve 99.9999999% (nine 9's) data durability.
By usage
Category | Description |
System disks |
|
Data disks | Storage for user data, logs, and applications (created independently or with instances) |
By performance tier
ESSD-series disks
Category
Feature
Use cases
Billing
High IOPS.
Low latency.
Latency-sensitive applications or I/O-intensive business scenarios, such as:
Large-scale online transaction processing (OLTP) databases
NoSQL databases
Elasticsearch distributed logs
Capacity fees.
Decouple capacity from performance.
Option to enable the provisioned performance.
Option to enable the burst performance.
Performance scaling without capacity expansion.
Fluctuating workloads requiring burst capabilities.
All scenarios for which ESSDs are suitable.
Capacity fees.
Pay-as-you-go provisioned performance fees if it is enabled.
Pay-as-you-go burst performance fees if it is enabled.
High IOPS.
Zone-redundant storage.
Multi-zone disaster recovery for databases.
Cross-zone container deployment.
Self-managed or cloud-based Software as a Service (SaaS) services.
All scenarios for which ESSDs are suitable.
Capacity fees.
ESSD Entry disks
NoteESSD Entry disks can be attached to only instances of universal instance families and e economy instance families.
High IOPS.
Low latency.
Development and testing business
Usage as system disks.
Capacity fees.
Previous generation disks
Standard SSDs, ultra disks, and basic disks are cloud disks of the previous generation. They are unavailable for purchase in specific regions and zones. We recommend that you use ESSDs at performance level 0 (PL0 ESSDs) or ESSD Entry disks instead of ultra disks and basic disks, and use ESSD AutoPL disks instead of standard SSDs.
Category
Feature
Use cases
Billing
Standard SSDs
High random read/write performance.
High reliability.
I/O-intensive applications
Small and medium-sized relational databases and NoSQL databases
Capacity fees.
Ultra disks
High cost efficiency.
High reliability.
Development and testing business
Usage as system disks.
Capacity fees.
Basic disks
High cost efficiency.
Low-cost development and testing business that does not require high storage performance
Capacity fees.
Local disks
Local disks provide local storage for ECS instances and reside on the physical machines that host the instances. Local disks are suitable for scenarios that require high storage I/O performance, mass storage, and high cost efficiency. Alibaba Cloud provides two categories of local disks:
Category | Supported instance family | Scenario |
Local non-volatile memory express (NVMe) SSD | The following instance families use local NVMe SSDs:
| Instance families equipped with local NVMe SSDs are suitable for the following scenarios:
|
Local SATA HDD | The d3s, d2c, d2s, d1ne, and d1 big data instance families use local SATA HDDs. | Local SATA HDDs are the preferred storage media for industries such as Internet and finance that have high requirements for big data computing, storage, and analytics. These disks are suited for mass storage and offline computing scenarios and can meet the high requirements of distributed computing services such as Hadoop in terms of storage performance, storage capacity, and internal network bandwidth. |
This topic describes the local disks that are purchased together with ECS instances. For information about the performance of instance families that are equipped with local SSDs and big data instance families, see Overview of instance families.
Elastic ephemeral disks
An elastic ephemeral disk is a block storage device that can be created alongside an ECS instance or separately created, with user-defined capacity for temporary data storage. It features high performance and cost-effectiveness. For more information, see Elastic ephemeral disks.
Performance of block storage devices
The performance of block storage devices varies based on the device category. Refer to the following topics:
Data security
The following features, except for the data erasure mechanisms, are unique to cloud disks and elastic ephemeral disks.
Distributed triplicate mechanism
Automatically replicates data across three physical nodes
Ensures 99.9999999% data durability during read/write operations.
Cloud disks only.
For more information, see Triplicate storage.
Proactive backup
Create snapshots for disks on a regular basis to enhance data security.
Use automatic snapshot policies for hands-free backups.
For more information, see Overview of snapshots and Automatic snapshot policies.
Data erasure mechanisms
Instant Blocking:
Deleted areas show zeros immediately.
Overwritten data becomes unreadable by updating location records.
Physical Removal:
Leftover data pieces are permanently wiped from disks.
Uses secure methods to prevent recovery.
Full Reset:
When you delete a disk:
All access records are destroyed.
Disk space is thoroughly cleared.
New users get a "blank" disk showing only zeros.
Data encryption
For sensitive data protection:
Auto-Encryption:
Encrypts data during transfer (ECS to disk).
Decrypts automatically when accessed.
AES-256 Security:
Protects both cloud disks and snapshots.
Meets banking-grade security standards.
For more information, see Encrypt cloud disks.
Billing
For information about the billing methods and billable items of Block Storage, see Block storage devices.
Limits
For information about the limits and quotas of Block Storage, see the Block storage devices section in the "Limits" topic.
Operations
Common operations on cloud disks
You can create a cloud disk together with an ECS instance or separately create a cloud disk. For information about the common operations that you can perform on a cloud disk, see Guide to creating and using disks.
Common operations on local disks
You can create and release local disks only together with instances of specific instance types. For more information, see Local disks.
Common operations on elastic ephemeral disks
Elastic ephemeral disks can be created alongside an ECS instance or separately created. For more information, see Use elastic ephemeral disks.
Other Alibaba Cloud storage services
In addition to Block Storage, Alibaba Cloud provides other storage services, such as Object Storage Service (OSS) and File Storage NAS (NAS), to meet your business requirements in different scenarios. For more information, see Comparison of NAS, OSS, and EBS.