TencentDB for SQL Server supports three types of instance deployment architectures: single-node, two-node, and multi-node. These instance deployment architectures are divided into local disk architecture and cloud storage architecture based on the storage type. This document describes the differences between the local disk architecture and the cloud disk architecture of TencentDB for SQL Server. Supported Storage Types and Database Versions of Instance Deployment Architectures
You need to understand the instance deployment architectures provided by the product and the corresponding storage types and database versions supported for deployment. The following table lists the supported storage types and database versions of different instance deployment architectures. You can configure them when creating an instance as needed. In addition, you can also directly learn about instance deployment architectures on the purchase page. |
Single-node (non-read-only instance) | Premium Disk Cloud SSD Balanced SSD Enhanced SSD | SQL Server 2012/2014/2016/2017/2019/2022 Enterprise | Single-node (cloud disk) |
Single-node (read-only instance) | High-performance local SSD | SQL Server 2012/2014/2016/2017/2019/2022 Enterprise | Read-only instance (local disk) |
| Balanced SSD Enhanced SSD |
| Read-only instance (cloud disk) |
Two-node | High-performance local SSD | SQL Server 2012/2014/2016/2017/2019 Enterprise | Two-node (local disk) |
| Balanced SSD Enhanced SSD | SQL Server 2017/2019/2022 Enterprise | Two-node (cloud disk) |
Multi-node | High-performance local SSD | SQL Server 2017/2019/2022 Enterprise | Multi-node (local disk) |
| Balanced SSD Enhanced SSD |
| Multi-node (cloud disk) |
After learning about the instance deployment architectures, you can select a storage type for mounting to your instance. Generally, TencentDB for SQL Server can offer genuinely authorized, stable, high-performance, and highly reliable database services, regardless of whether you select local disks or cloud disks. The local disk architecture and cloud storage architecture vary slightly in performance, supported features, and other aspects. For details, see the following descriptions.
Differences Between Local Disk Architecture and Cloud Disk Architecture
Difference 1: Performance
The performance of instances with the local disk architecture differs from that of instances with the cloud disk architecture. For details, see Performance Test Report. Difference 2: Features
Both the local disk architecture and the cloud disk architecture support common features, such as instance creation, instance connection, database creation, and account creation. However, the cloud disk architecture also supports the following features.
|
Cloud disk architecture | Supports more regions outside the Chinese mainland for deployment. | Included regions: São Paulo, Virginia, Frankfurt, Singapore, Jakarta, and Bangkok. |
| | If replica node read-only is enabled, replica nodes can be accessed through their unique read-only addresses, which can reduce the read request load of the primary node and effectively save read-only instance costs. |
| | A primary-replica switch can be triggered manually when an instance fault occurs to switch the secondary database to the primary database, ensuring system availability and data integrity. |
| Supports later editions. | SQL Server 2022 Enterprise is supported. |
| | The instance-level character set collation can be modified during instance creation to meet users' self-service setting needs for the default character set. |
| | The system time zone can be modified during instance purchase to meet the needs of customers outside the Chinese mainland for the local time zone. |
| | Data can be stored on disks in ciphertext. When data is read from or written to disks, it can be automatically encrypted or decrypted, enhancing data storage security. |
Difference 3: Impact of Configuration Adjustments
The impacts of configuration adjustments are different between the local disk architecture and the cloud disk architecture. The specific impacts are as follows.
Local disk architecture: If local resources are sufficient during a specification upgrade or disk capacity expansion, an in-place upgrade is performed on the instance, without affecting the business. If local resources are insufficient, an upgrade through migration is performed on the instance. The migration time consumption depends on data volume. After migration, a switch is performed, causing a second-level momentary disconnection from the database. Ensure the business has a reconnection mechanism.
Cloud disk architecture: During disk capacity expansion on an instance, in-place expansion is performed on the instance, without triggering a restart or momentary disconnection. This avoids impact on the business. During an upgrade or a downgrade of specifications (CPU and memory), the instance is restarted, resulting in service unavailability for approximately 1 to 3 minutes. Perform the operation during off-peak hours of the business.
Difference 4: Number of Replica Nodes
The difference in the number of replica nodes only exists between the multi-node (local disk) architecture and the multi-node (cloud disk) architecture. The specific difference is as follows.
Multi-node (local disk): To purchase an instance of this architecture, submit a ticket for application first. You can consult the supported number of replica nodes under this architecture using the ticket. Multi-node (cloud disk): The number of supported replica nodes ranges from 2 to 5. When configuring replica nodes in the console or on the purchase page, you can select any AZ that is not sold out in the selected region.
Difference 5: Maximum Storage Space
Currently, the maximum storage space is 6,000 GB for the local disk architecture and 32,000 GB for the cloud disk architecture.
Summary
Both TencentDB for SQL Server instances with the local disk architecture and those with the cloud disk architecture can provide genuinely authorized, stable, high-performance, and highly reliable database services, with only slight differences in performance, supported features, and other aspects. In terms of performance, Enhanced SSD cloud disks have the same performance as local disks. In terms of features, the cloud disk architecture supports more features, and more new features will be supported for this architecture in the future. In terms of storage, the cloud disk architecture supports a super large storage capacity.