Regional ESSD is a new cloud disk category for Elastic Compute Service (ECS) instances, enabling automatic data storage across multiple zones within the same region. These disks are physically separate from data centers, racks, and power supplies, providing data protection against physical zone failures and ensuring continuous read and write operations for business continuity. This topic describes the specifications, billing, limits, and common operations of Regional ESSDs.
Cloud disk overview
Cloud disk advantages
Regional ESSDs offer several advantages over other cloud disk categories:
Eliminate the need to manage complex traditional offline storage replication logic. Regional ESSDs use physical replication and support write-through across multiple zones, achieving an RPO of zero.
For application-layer disaster recovery, there's no need to acquire additional ECS instances, bandwidth, or computing resources. Regional ESSDs offer enhanced business continuity.
Regional ESSDs inherit enterprise-level features supported by ESSDs.
Due to the need for synchronous writing across multiple zones, the average write latency for Regional ESSDs is higher than that of ESSD PL1 disks. If your business requires zero data loss in the event of zone failures and can accommodate increased write latency, Regional ESSDs are a suitable option.
Scenarios
Multi-zone disaster recovery for databases
Traditional database deployment solutions use primary/secondary replication for high availability and cross-zone disaster recovery, but they can suffer from replication latency and data inconsistency. With Regional ESSD deployment, you can opt for a cost-effective pattern by deploying a single compute node in one zone (Zone A) with a Regional ESSD attached. There's no need for additional compute nodes in another zone (Zone B) or primary/secondary replication configuration. Physical replication features of Regional ESSDs handle cross-zone data redundancy. In case of a failure in Zone A, simply deploy a compute node in Zone B, attach the Regional ESSD, and continue service provision, reducing storage costs by 25% and computing costs by 50%.
Cross-zone container deployment
Stateful applications' cross-zone elasticity and disaster recovery pose significant challenges in container deployment. Regional ESSDs provide cross-zone disaster recovery capabilities for stateful applications in individual zones at no additional cost. If a compute node or zone fails, or if resources in a zone are insufficient, containers can migrate to another zone without complex data synchronization or verification.
Build self-managed Software as a Service (SaaS) services or deploy SaaS services in the cloud
Deploying self-managed SaaS services or cloud-based SaaS services requires two sets of ECS clusters in two zones. Regional ESSDs provide a low-cost solution for cross-zone capabilities.
Billing description
Regional ESSDs are billed based on disk capacity, with options for pay-as-you-go or subscription billing methods. For detailed billing rules, see block storage billing.
Limits
Region limits
Available only in China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Shenzhen), Hong Kong (China), and Singapore.
Instance family limits
For a list of instance families that support Regional ESSDs, see instance families.
Feature limits
Feature classification | Feature point | Is Regional ESSD supported |
Basic features of cloud disks | Create, view, modify, and release | Yes |
Data encryption | Encrypt | Yes |
Cloud disk multi-attach | Multi-attach | Yes |
Async replication | Asynchronous replication |
|
Data protection | Create snapshots and use the instant access feature | Yes |
Automatic snapshot policy | Yes | |
Create cloud disks from snapshots | Yes | |
Create snapshot-consistent groups | No | |
Cloud disk operations | Initialize cloud disks | Yes |
Resize the system disk | Yes | |
Roll back a disk by using a snapshot | Yes | |
Usage as system disks | No Note Regional ESSDs can be used only as data disks. | |
Mount a disk | Yes | |
Billing methods | Changing billing methods | Yes |
Disk specifications | Change disk type | No |
Performance elasticity | Configure performance provisions | No |
Configure burst performance | No |
Cloud disk performance
The table below details the specifications of Regional ESSDs.
Performance category | Description |
Capacity range (GiB) | 10~65,536 |
Maximum IOPS per disk | 50,000 |
Maximum I/O size (KB) | 16 |
Maximum throughput per disk (MB/s) | 350 |
Average one-way random write latency (ms) | Milliseconds① |
Formula for calculating the IOPS per disk (baseline performance) | min{1,800+50×Capacity, 50,000} |
Formula for calculating the throughput performance per disk (baseline performance, in MB/s) | min{120+0.5×Capacity, 350} |
①Latency may vary across different regions and zones. You can test the average write latency of Regional ESSDs by referring to test block storage performance.
Use regional ESSD
Create regional ESSD
Create with instance
Navigate to the instance creation page.
Select the Custom Launch tab.
Configure necessary parameters such as Billing Method, Region, Instance Type, and Image. When creating a Regional ESSD, consider the following:
Choose a region that supports Regional ESSDs.
In the Storage section, select Regional ESSD as the data disk type and set the disk capacity.
For more details on other parameters, refer to custom purchase instance.
Create separately
Log on to the ECS console.
In the left-side navigation pane, choose .
In the top navigation bar, select the region and resource group to which the resource belongs.
Click the Disks tab, then click Create Disk.
Set the parameters.
Choose a region that supports Regional ESSDs.
Select Regional ESSD as the disk type and set the disk capacity.
For more details on other parameters, refer to create an empty data disk.
Attach the newly created Regional ESSD to an ECS instance and initialize it.
For guidance, see attach a data disk.
Force attach regional ESSD
If a data center-level or instance-level fault occurs, you may be unable to detach a Regional ESSD from an ECS instance. In this case, you can force attach the Regional ESSD to a different ECS instance in the same region without detaching it from the original instance, speeding up service recovery.
The force attach operation is exclusive to Regional ESSDs. For other cloud disk categories, you must detach the disk from the original ECS instance before attaching it to a different one.
Log on to the ECS console.
In the left-side navigation pane, choose .
In the top navigation bar, select the region and resource group to which the resource belongs.
Locate the disk you want to operate on under the Disks tab and click Attach in the Operation column.
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Select the target instance to which you want to attach the disk and specify the release behavior. Click I Confirm To Switch The Attached Instance Of The Disk By Force Attach, and then follow the on-screen instructions to complete the disk attachment and initialization.
If the original ECS instance has data not written to the Regional ESSD, such as data in memory, the instance will reject I/O requests related to the Regional ESSD and return failures for those requests after you force attach the Regional ESSD to a different ECS instance.