A Regional Enterprise SSD (ESSD) is a new type of ESSD Cloud Disk. Data written to a Regional ESSD is automatically replicated across multiple Availability Zones, each with its own data center, rack, and power supply. If a physical failure occurs in one Availability Zone, the disk continues to provide uninterrupted service, ensuring Business Continuity. This topic describes the specifications, billing, limitations, and common operations for Regional ESSDs.
Regional ESSD
Advantages
A Regional Enterprise SSD (ESSD) offers the following advantages over other Cloud Disk products:
Zero Recovery Point Objective (RPO): Regional ESSDs handle physical data replication automatically with synchronous writes across multiple Availability Zones. This eliminates the need to manage complex replication logic, a common requirement for on-premises storage solutions.
Enhanced Business Continuity at a lower cost: You can achieve application-level disaster recovery without purchasing additional ECS instances, bandwidth, or compute resources, common in manual failover setups.
Regional ESSDs retain the same enterprise-grade features as standard ESSDs, ensuring a consistent user experience.
Synchronous data replication across Availability Zones results in a slightly higher average write latency for a Regional ESSD compared to a PL1 ESSD. Therefore, a Regional ESSD is ideal for applications that require zero Data Loss from an Availability Zone failure and can tolerate a minor increase in write latency.
Use cases
High-availability databases across multiple Availability Zones
Traditional database deployments use Primary/Secondary Replication to achieve High Availability and disaster recovery across Availability Zones. However, this approach introduces potential issues such as replication delays and data inconsistency between the primary and secondary nodes. With a Regional ESSD, you can adopt a more cost-effective deployment model. You only need to deploy a Compute Node in Availability Zone A and attach the Regional ESSD. You do not need to deploy a second Compute Node in Availability Zone B or configure Primary/Secondary Replication. The disk's underlying physical replication handles data redundancy across zones automatically. In the event of a failure, you can simply launch a new Compute Node in Availability Zone B and attach the disk to restore service. This can reduce storage costs by up to 25% and compute costs by up to 50%.
Deploy containers across Availability Zones
Container deployments often face challenges in ensuring elasticity and disaster recovery for stateful applications across multiple Availability Zones. Using Regional ESSDs, you can upgrade a single-zone stateful application to a multi-zone, disaster-resilient application with no code changes. If a Compute Node or an entire Availability Zone fails, or if resources in one zone become insufficient, you can migrate the Container to another Availability Zone without complex data synchronization or Data Validation.
Build or deploy Software as a Service (SaaS) applications
When you build or deploy a Software as a Service (SaaS) application, you typically need to set up two parallel ECS clusters in two different Availability Zones to ensure high availability. Regional ESSDs provide a low-cost solution for cross-zone capabilities.
Billing
Billing for Regional Enterprise SSDs (ESSD) is capacity-based. Both pay-as-you-go and subscription billing models are supported. For detailed billing rules, see Block storage devices.
Limitations
Region limitations
Regional ESSDs are available only in the following regions: China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Shenzhen), China (Ulanqab), China (Hong Kong), Singapore, Malaysia (Kuala Lumpur), and Indonesia (Jakarta).
Instance type limitations
For information about the instance families that support Regional ESSDs, see Instance family overview.
Feature limitations
Feature type | Feature | Supported by Regional ESSDs |
Basic features of cloud disks | Create, view, modify, and release disks. | Yes |
Data encryption | Encrypt | Yes |
Shared block storage | Multi-attach | Yes |
Disk async replication | Perform async replication. |
|
Data protection | Create snapshots and use the instant access. | Yes |
Create automatic snapshot policy. | Yes | |
Create cloud disks from snapshots. | Yes | |
Create snapshot-consistent groups. | Yes You can create a snapshot group for a regional ESSD only with other disks of the same type. | |
Cloud disk operations | Initialize cloud disks. | Yes |
Resize cloud disks. | Yes | |
Roll back a cloud disk by using a snapshot. | Yes | |
Use as a system disk. | No Regional ESSDs can be used only as data disks. | |
Attach a cloud disk to an ECS instance. | Yes | |
Disk billing | Change the billing method of a cloud disk. | Yes |
Disk specifications | Change disk category. | Yes |
Performance elasticity | Configure performance provisions. | No |
Configure burst performance. | No |
Disk performance
The following table describes the specifications of Regional ESSDs.
Metric | Description |
Capacity range (GiB) | 10 to 65,536 |
Maximum IOPS per disk | 50,000 |
Maximum I/O size (KiB) | 16 |
Maximum throughput per disk (MB/s) | 350 |
Average random write latency per connection (ms) | Several milliseconds① |
IOPS performance formula (Baseline Performance②) | min{1,800 + 50 × Capacity, 50,000} |
Throughput performance formula (Baseline Performance, MB/s) | min{120 + 0.5 × Capacity, 350} |
①Latency varies by Region and Availability Zone. You can test the average write latency of your Regional ESSD. For more information, see Test for block storage devices.
②Baseline performance: The maximum IOPS and throughput that a Cloud Disk provides after it is created. The baseline performance increases linearly with the disk capacity up to a specified maximum value, which varies based on the disk specifications.
Use a Regional ESSD
Create a Regional ESSD
Create a disk with an instance
Go to the ECS instance buy page.
Click the Custom Launch tab.
Configure parameters such as the billing method, Region, Instance Type, and Image. Pay attention to the following parameters when you create a Regional ESSD:
Select a region that supports Regional ESSDs.
In the Storage section, set the data disk category to Regional ESSD and configure the disk size.
For information about other parameters, see Custom launch ECS instances.
Create a standalone disk
Go to ECS console - Block Storage.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
Click Create Cloud Disk.
Configure the parameters.
Select a region that supports Regional ESSDs.
Set the disk category to Regional ESSD and configure the disk size.
For information about other parameters, see Create an empty data disk.
Attach the new Regional ESSD to an ECS instance and initialize it before use.
For more information, see Attach data disk.
Force attach a Regional ESSD
If a data center failure or an ECS instance exception prevents you from detaching a Regional ESSD, you can force-attach it. This allows you to attach the disk directly to another ECS instance in the same Region without first detaching it, accelerating service recovery.
The force attach feature is available only for Regional Enterprise SSDs (ESSD). Other types of Cloud Disks must be detached before they can be attached to another instance.
Go to ECS console - Block Storage.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
Find the disk that you want to attach and click Attach in the Actions column.
Select the target instance and its release behavior. Select I confirm to move the disk to another instance by using the force attach feature, and then follow the on-screen instructions to complete the attachment and initialization process.
After a force-attach, any data in the original instance's memory cache that has not yet been written to the disk is lost, and subsequent I/O requests from that instance will fail.
Reference
To change the disk type of a Regional ESSD for performance tuning or capacity expansion, see Change disk category.