Model Selection
Last updated: 2025-08-07 17:27:41
How do I select an appropriate architecture of TencentDB for SQL Server?
TencentDB for SQL Server supports the single-node (formerly Basic Edition) architecture, two-node (formerly HA Edition/Cluster Edition) architecture, and multi-node architecture. To ensure the high availability of instances, it is recommended that you select the two-node (formerly HA Edition/Cluster Edition) architecture or multi-node architecture and adopt cross-AZ high availability deployment. If there is a strong dependency on the granting of the sysadmin permission, you can select the single-node (formerly Basic Edition) architecture and submit a ticket to apply to create an account with the sysadmin permission. The differences between these architectures are as follows:
Single-node (formerly Basic Edition): Single-node deployment, with storage-computing separation and 3-replica storage based on Premium Disk to prevent data loss.
Two-node (formerly high-availability/cluster edition):
SQL Server 2008 R2, 2012, 2014, 2016 Enterprise/Standard: They support the database mirroring (high-availability replication) scheme to enable automatic switch in seconds, lowering the data loss to "zero".
SQL Server 2017, 2019 Enterprise/Standard: They adopt the Always On technology to build a SQL Server cluster that features high performance, high availability, high reliability, and easy maintenance.
Multi-node: It supports versions SQL Server 2017, 2019, and 2022 Enterprise, featuring a one-primary-multiple-secondary architecture. 2 to 5 secondary nodes can be deployed, and different secondary nodes can be deployed in different AZs, ensuring high availability and significantly enhancing the disaster recovery capability of the database.
How do I select the architecture and version of TencentDB for SQL Server if a read-only feature is required?
If read-only instances are required, we recommend that you use SQL Server 2017/2019 Enterprise two-node (formerly high-availability/cluster edition) instances to sync data more efficiently and stably. For more information, see Read-Only Instance Overview and Read-Only Instance Specifications.
How is the performance of TencentDB for SQL Server?
TencentDB for SQL Server provides the single-node architecture (formerly basic edition) and primary/replica two-node architecture (formerly high-availability/cluster edition):
The highest TPM of the single-node architecture (formerly basic edition - premium cloud disk) is 1.32 million.
The highest TPM of the single-node architecture (formerly basic edition - SSD) is 1.38 million.
The highest TPM of the primary/replica two-node architecture (formerly high-availability/cluster edition) is 4.58 million.
Which specifications does TencentDB for SQL Server support?
For specifications of TencentDB for SQL Server single-node (formerly Basic Edition), dual-node (formerly HA Edition/Cluster Edition), and multi-node primary instances, see Primary Instance Specification List. For specifications of read-only instances, see Read-Only Instance Specification List.
How do I select an appropriate TencentDB for SQL Server instance specification?
The TencentDB for SQL Server instance specification can be selected based on two factors: required storage capacity and performance. For supported instance specifications, see Primary Instance Specifications and Read-Only Instance Specifications. For performance details, see Performance Test Report.
In which regions is TencentDB for SQL Server available?
What versions does TencentDB for SQL Server support?
Supported versions: 2008R2 Enterprise, 2012 Enterprise, 2014 Enterprise, 2016 Enterprise, 2017 Enterprise, 2019 Enterprise.
How is the compatibility of TencentDB for SQL Server?
TencentDB for SQL Server is backward compatible. For example, you can upgrade or migrate TencentDB for SQL Server 2016 to 2019 but cannot downgrade or migrate TencentDB for SQL Server 2019 to 2016.
What features does TencentDB for SQL Server offer?
Supported features vary by TencentDB for SQL Server edition. For more information, see Features and Differences and Constraints and Limits.
What are the differences in the features supported by different versions of TencentDB for SQL Server?
For features supported by different TencentDB for SQL Server editions, see Features and Differences.
How many databases can I create at most in a TencentDB for SQL Server instance?
In terms of performance for TencentDB for SQL Server, having too many databases can lead to a decline in instance performance, consuming resources such as worker threads. Moreover, exceeding the database creation quantity limit can easily cause primary/secondary synchronization exceptions. It is recommended that the number of databases created for a single instance should not surpass its upper limit. The number of databases that a single instance can handle is related to the instance's CPU core count. For the detailed computational formula of the maximum number of databases for each version, see Database Quantity.
You can also use SSMS to connect to the instance and create databases, and databases created via SSMS will be automatically synced to the replica instance. However, to avoid exceptions during primary-replica sync, we recommend that you not create more databases than the specified limit.
Does TencentDB for SQL Server support real-time hot backup?
TencentDB for SQL Server dual-node (formerly HA Edition/Cluster Edition) instances support real-time hot backup, featuring a one-primary-one-secondary architecture. Multi-node instances also support real-time hot backup, and allow the creation of one-primary-two-secondary, one-primary-three-secondary, one-primary-four-secondary, and one-primary-five-secondary architectures.
What are the use cases of TencentDB for SQL Server?
TencentDB for SQL Server can be used in various use cases, including industry utility, mobile OA, gaming, healthcare, medicine, media, internet, IoT, retail, ecommerce, logistics, securities, technical service, automobile, travel, and finance. For more information, see Use Cases.
What high availability and disaster recovery capabilities does TencentDB for SQL Server have?
TencentDB for SQL Server provides disaster recovery capabilities at different levels, including instance, server, data center, AZ, and region, to ensure the business continuity on healthy systems with the minimum data loss in case of natural disasters, device failures, and maloperations.
Backup is the basis of all disaster recovery systems and the last line of defense in the high data availability architecture. TencentDB for SQL Server features rich backup capabilities, ensuring that the data can be restored quickly even after a total system crash to guarantee the business continuity as much as possible.
TencentDB for SQL Server provides instances in various architectures with guaranteed high availability:
Multi-node instance, which supports versions SQL Server 2017/2019/2022 Enterprise, featuring a one-primary-multiple-secondary architecture (with 2 to 5 secondary nodes). It is deployed on the physical server at the bottom layer and uses AlwaysOn technology to build high-performance, highly available, reliable, and easy-to-maintain SQL Server clusters, providing second-level HA automatic switch.
A SQL Server 2008R2/2012/2014/2016 Enterprise two-node (formerly high-availability/cluster edition) instance is in the primary/replica two-node architecture, where the underlying layer is deployed on a physical machine. It supports the database mirroring (high-availability replication) scheme to implement automatic HA switch within seconds.
A SQL Server 2017/2019 two-node (formerly high-availability/cluster edition) instance is in the primary/replica two-node architecture, where the underlying layer is deployed on a physical machine. It adopts the Always On technology to build a SQL Server cluster that features high performance, high availability, high reliability, and easy maintenance and implements automatic HA switch within seconds.
A single-node (formerly basic edition) instance is in the single-node architecture, where the underlying layer is deployed in a CVM instance, storage and computing are separated, and data is stored in three copies in premium cloud disk to avoid data loss. In extreme cases where an instance fails, a new instance will be started to automatically restore the data from data and log backups. The specific restoration time is subject to the data volume. The servers of two TencentDB instances are usually on the same physical machine.
For intra-city disaster recovery, the multi-AZ deployment capability is provided. The private networks between AZs are interconnected within the same region, and fault isolation can be achieved between AZs. For dual-node primary/secondary instances and multi-node instances, primary and secondary nodes can be distributed across different AZs within the same region (for example, one primary node in the primary AZ and one secondary node in the secondary AZ). This enhances business continuity to prevent database instance failures or AZ interruptions. Additionally, users can manually perform switch via the console to verify the robustness of the business. Switch within an AZ or between AZs is transparent to applications.
For remote disaster recovery, cross-region backup capabilities are offered to store backup files in another region. You can set the cross-region backup retention period and multiple backup regions. After a cross-region backup policy is enabled, the instance backup files will be automatically stored in the target region. In this way, if an instance in a region fails, you can restore its backup files in the remote region to a new instance there for guaranteed business continuity. Cross-region backup implements the high availability of database restoration and meets the requirements for data availability and security, remote backup and restoration, remote disaster recovery, long-term data archive, and regulation compliance.
In addition, TencentDB for SQL Server also has rich backup capabilities to guarantee the data security and prevent data loss or corruption. Specifically, you can configure automatic backup, manual backup, data backup, log backup, backup file format (unarchived files or archive file), instance backup, and multi-database backup. You can also customize the backup policy, backup retention period (7–1,830 days), and backup cycle.
Moreover, TencentDB for SQL Server comes with comprehensive disaster recovery capabilities at both the data and business management layers. Cross-region disaster recovery for databases is meaningful only if the business also features cross-region disaster recovery. However, cross-region distributed deployment of the business inevitably causes the split-brain problem. At the business management layer, the business is deployed in three AZs (two intra-region AZs and one remote AZ) to ensure the business continuity. Before an actual failover occurs, the system will always check whether the database sync status (database sync system table) is normal to avoid faulty failover.
What strengths does TencentDB for SQL Server have?
TencentDB for SQL Server is licensed by Microsoft to continuously provide you with the latest features, so you can avoid any risks arising from unauthorized software use. It features out-of-the-box usage, high stability, reliability, and security, elastic scaling, data security protection, and failover in seconds, allowing you to focus on application development.
Diverse versions: 3 deployment architectures are provided, that is, single-node (formerly Basic Edition), dual-node (formerly HA Edition/Cluster Edition), and multi-node, fully ensuring the high availability of services.
Official license: Licensed by Microsoft, TencentDB for SQL Server continuously provides you with the latest features, helping you avoid the risks of using unauthorized software and enhance the trustworthiness of your business in competitive markets.
Excellent performance: The new ultra-high specification of 90-core 720 GB MEM is released, with a TPM of up to 4.5 million. Both performance and cost performance have been improved by more than 30% once again, breaking Tencent Cloud's own performance record in the industry.
High stability and reliability: TencentDB for SQL Server delivers a 99.9996% data reliability and 99.95% service availability. It provides easy-to-use cloud-based control capabilities, such as monitoring and alarming, backup and restoration, data migration, and elastic scaling.
Ease of management: Various management tasks can be finished with ease in the Tencent Cloud console or SSMS, such as database management, permission configuration, and monitoring and alarming. This eliminates your concerns over database installation and Ops.
Monitoring and alarming: Dozens of key metrics can be viewed in the console, such as the number of connections and requests, disk I/O, and buffer hit rate, helping you comprehensively monitor database conditions and accurately understand the database load and system health. User-defined resource threshold alarms are supported to help you discover database exceptions timely and resolve potential system problems quickly.
BI: SSIS + BI analysis services are provided, which integrate data storage, ETL, and visual analysis to help meet your diversified needs in various use cases, including BI analysis, high-value data mining, and primary data management system setup.
What strengths does TencentDB for SQL Server have over self-built SQL Server?
TencentDB for SQL Server has the following strengths over self-built databases:
Feature | TencentDB for SQL Server | Self-Built SQL Server |
Service availability | You have to guarantee the service availability and set up primary/replica replication and RAID capabilities on your own. | |
System security | Anti-DDoS is supported, and various database security vulnerabilities are fixed in time. The data security meets all mainstream national and international security standards. | You have to deploy security services and fix vulnerabilities on your own at high costs. Security compliance is not guaranteed, and the security requirements cannot be quickly met. |
Database performance | High-performance devices with a TPM of up to 4.5 million are used. For more information, see Performance Test Report. | General devices without optimization and fine-tuning are used. |
Software and hardware investment | No hardware or software investment is required, and the service is pay-as-you-go. | Database servers are costly. |
System hosting | There are no hosting fees. | The hosting fees are high. |
Deployment and scaling | The out-of-the-box service can be quickly deployed and elastically scaled. | You have to purchase hardware devices, host them in data centers, and deploy them on your own. You also have to solve stability problems and set up many supporting modules and management tools, which require heavy investments in technology and take a long period of time. |
Resource utilization | The service is billed by the actual usage and supports elastic scaling to ensure a high resource utilization. | You have to consider traffic spikes, and the resource utilization is low. |
Data disaster recovery | Primary/replica replication and backup are configured by default. Both intra-region and cross-region disaster recovery schemes are supported, such as multi-AZ deployment and cross-region backup. | You have to find the backup storage space and regularly verify whether backups can be restored, which cost more money and time. |
Control and management services | Comprehensive cloud-based instance lifecycle management capabilities are available for various objects, including monitoring and alarming, backup and restoration, instance, database, account, network, parameter, and log. | You have to implement all control and management capabilities on your own. |
Procurement costs | Instances are priced transparently and even more cost-effective than CVM. | In addition to instances, you also have to set up disaster recovery, monitoring, and management systems on your own at totally uncontrollable costs. |
License | Official licenses from Microsoft continuously provide you with the latest features, eliminating your need to purchase additional licenses. | Pirated services lead to legal risks, while official licenses are expensive. |
Ops costs | Tencent Cloud provides a professional team to guarantee the service quality for key accounts 24/7, eliminating your need to manually perform Ops. | You have to hire dedicated DBAs for database maintenance, which incurs high labor costs. |
How do I migrate data to TencentDB for SQL Server?
You can migrate data from self-built SQL Server databases in local IDCs, CVM instances, and cloud servers provided by other cloud vendors, cloud SQL Server databases provided by other cloud vendors, and TencentDB for SQL Server databases to TencentDB for SQL Server through either cold backup migration or DTS as appropriated based on your business scenarios.
If your business allows you to shut down the database for backup, you can use cold backup migration, i.e., restoring data from .bak backup files to migrate the source database to a TencentDB for SQL Server instance. You can download COS files or upload local files for migration. Three data restoration modes are supported: full backups, full backups + log backups, and full backups + differential backups.
If your business doesn't allow you to shut down the database and requires smooth migration, you can migrate with DTS. DTS supports two migration modes: full migration and full + incremental migration. It supports multiple access types, such as public network, self-build on CVM, Direct Connect, VPN, CCN, and database.
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