Regional Enterprise SSD (ESSD) is a new cloud disk category for Elastic Compute Service (ECS) instances. Data written to a Regional ESSD can be automatically stored in multiple zones within the same region. Regional ESSDs are physically isolated from data centers, racks, and power supplies. In the event of physical failures in a zone, the Regional ESSD can prevent data loss and allow for continuous reads and writes to ensure business continuity. This topic describes the specifications, billing, limits, and common operations of Regional ESSDs.
Regional ESSD
Benefits
Regional ESSDs have the following advantages over other categories of cloud disks:
You do not need to be familiar with the complex data replication logic of traditional offline storage. You can replicate data by using Regional ESSDs to achieve a recovery point objective (RPO) of 0.
During application-layer disaster recovery, you do not need to purchase additional ECS instances, bandwidth, or computing resources. You can use Regional ESSDs to achieve better business continuity.
Regional ESSDs inherit enterprise-level features that ESSDs support.
Scenarios
Multi-zone disaster recovery for databases
The traditional database deployment solution uses primary/secondary replication to achieve high availability and implement disaster recovery across zones. The solution has issues, such as primary/secondary replication latency and inconsistent data during preparation. Regional ESSDs allow you can choose the lowest-cost deployment pattern. You need to only deploy compute nodes in Zone A and attach Regional ESSDs to Zone A. You do not need to deploy compute nodes in Zone B or configure primary/secondary replication. You can directly use the physical replication feature of Regional ESSDs to implement data redundancy across zones. If a failure occurs in Zone A, you need to only deploy compute nodes in Zone B to provide services. This reduces storage costs by 25% and computing costs by 50%.
Cross-zone container deployment
The cross-zone elasticity and disaster recovery of stateful applications remain a major challenge in container deployment. Regional ESSDs provide stateful applications in individual zones with cross-zone disaster recovery capabilities at zero cost. If a compute node or a zone fails or the resources in a single zone are insufficient, the containers can be migrated to another zone without the need for complex data synchronization or data verification.
Build self-managed Software as a Service (SaaS) services or deploy SaaS services in the cloud
When you deploy self-managed SaaS services or deploy SaaS services in the cloud, you must build two sets of ECS clusters in two zones to deliver the corresponding services based on Regional ESSDs. Regional ESSDs provide low-cost cross-zone capabilities.
Billing
You are charged for disk capacity fees for Regional ESSDs. You can use the pay-as-you-go or subscription billing method. For information about the billing rules of Regional ESSDs, see Block storage devices.
Limits
Region limits
Regional ESSDs are available only in the China (Hangzhou) and China (Hong Kong) regions.
Instance type limits
All instance types that support ESSDs support Regional ESSDs. For more information, see Overview of instance families.
Feature limits
Feature type | Feature | Supported by Regional ESSDs |
Basic features of cloud disks | Create, view, modify, and release disks. | Yes |
Cloud data encryption | Encrypt data stored on cloud disks. | Yes |
Cloud disk multi-attach | Attach a cloud disk to multiple instances. | Yes |
Cloud disk async replication | Perform async replication. |
|
Data protection | Create snapshots and use the instant access feature. | Yes |
Create automatic snapshot policies. | Yes | |
Create cloud disks from snapshots. | Yes | |
Create snapshot-consistent groups. | No | |
Cloud disk operations | Initialize cloud disks. | Yes |
Resize cloud disks. | Yes | |
Roll back a cloud disk by using a snapshot. | Yes | |
Configure a system disk. | No Note Regional ESSDs can only be used as data disks. | |
Attach a cloud disk to an instance. | Yes | |
Billing of cloud disks | Change the billing method of a cloud disk. | Yes |
Disk specifications | Change the category of a cloud disk. | No |
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 |
Max IOPS/Min IOPS per disk | 50,000/2,300 |
Maximum I/O size (KB) | 16 |
Max throughput/Min throughput per disk (MB/s) | 350/125 |
Average one-way random write latency (ms) |
|
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} |
Use Regional ESSDs
Create Regional ESSDs
Create a Regional ESSD when you create an ECS instance
Go to the ECS instance buy page.
Click the Custom Launch tab.
Configure parameters, such as Billing Method, Region, Instance Type, and Image, based on your business requirements. Take note of the following parameters when you create a Regional ESSD:
Select a region in which Regional ESSDs are supported.
In the Storage section, set the data disk category to Regional ESSD and specify the size of the Regional ESSD.
For information about other parameters, see Create an instance on the Custom Launch tab.
Separately create a Regional ESSD
Log on to the ECS console.
In the left-side navigation pane, choose .
On the Block Storage page, click Create Cloud Disk.
Configure parameters based on your business requirements.
Select a region in which Regional ESSDs are supported.
In the Storage section, set the disk category to Regional ESSD and specify the size of the Regional ESSD.
For information about other parameters, see Create an empty data disk.
Attach the created Regional ESSD to an ECS instance and initialize the Regional ESSD.
For more information, see Attach a data disk.
Implement disaster recovery by using a Regional ESSD
In this example, Zone A in the China (Hangzhou) region is faulty. A Regional ESSD attached to an ECS instance in Zone A is restored in Zone B. Perform the following steps:
Detach the Regional ESSD from the ECS instance in Zone A. For more information, see Detach a data disk.
Attach the Regional ESSD to an ECS instance in Zone B. For more information, see Attach a data disk.
References
For information about common operations on Regional ESSDs, see Disks.
For information about limits on Regional ESSDs, see the Feature limits section of this topic.