TencentDB for SQL Server offers the following architectures: Basic Edition (single-node architecture), Dual-Server High Availability Edition (primary/replica dual-node architecture), and Cluster Edition (primary/replica dual-node architecture). To guarantee the instance's high availability, we recommend you select a dual-node architecture (Dual-Server High Availability or Cluster Edition). If your business requires to open the SA permissions, you can use the Basic Edition. Differences between those architecture editions are as detailed below:
If read-only instances are required, we recommend you use SQL Server 2017/2019 Enterprise Cluster Edition to sync data more efficiently and stably. For more information, see Read-Only Instance Overview and Read-Only Instance Specifications.
TencentDB for SQL Server provides the single-node architecture (Basic Edition) and primary/replica dual-node architecture (Dual-Server High Availability and Cluster Editions):
For more information, see Performance Test Report.
For specifications of TencentDB for SQL Server Basic, Dual-Server High Availability, and Cluster Edition instances, see Primary Instance Specifications. For specifications of read-only instances, see Read-Only Instance Specifications.
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.
For regions and AZs where TencentDB for SQL Server can be deployed, see Regions and AZs.
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.
For features supported by different TencentDB for SQL Server editions, see Features and Differences.
For performance considerations, we recommend you create databases in a TencentDB for SQL Server instance within the following limits:
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 you not create more databases than the relevant limit.
TencentDB for SQL Server Dual-Server High Availability/Cluster Editions both support real-time hot backup in a one-primary-one-replica architecture.
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.
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:
For intra-region disaster recovery, TencentDB for SQL Server provides multi-AZ deployment capabilities. Different AZs in the same region are interconnected over the private network, and failures can be isolated between AZs. For instances in the primary/replica dual-node architecture, the primary and replica instances can be deployed in different AZs in the same region (for example, one primary instance in the primary AZ and one replica instance in the replica AZ). This improves the business continuity and guarantees the data availability in case of instance failures or AZ disconnections. You can also manually switch between the primary and replica instances in the console to verify the business robustness. Switches within the same AZ and between different AZs are imperceptible to the application.
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.
Licensed by Microsoft, TencentDB for SQL Server continuously provides you with the latest features and helps you avoid the risks with unauthorized use of the software. It features out-of-the-box usage, high stability, reliability, and security, elastic scaling, data security protection, and failover in a matter of seconds, enabling you to focus more on application development itself.
TencentDB for SQL Server has the following strengths over self-built databases:
|Feature||TencentDB for SQL Server||Self-Built SQL Server|
|Service availability||For more information, see Service Level Agreement.||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||Genuine licenses from Microsoft continuously provide you with the latest features, eliminating your need to purchase additional licenses.||Pirated services lead to legal risks, while genuine 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.|
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.