This document describes tenant security features such as MAR, automatic failover, and data security encryption.
As a database records data in it, to switch between multiple databases, the data in them must be in sync. Therefore, data sync is the foundation of the database high availability solution.
Currently, the open-source MySQL database supports the async and semi-sync data replication modes. However, in both modes, if a node failure occurs, the data may be lost or become incorrect or messy. In addition, the replication mode is serial, which has a low performance.
In Tencent Cloud's proprietary parallel multi-thread asynchronous replication (MAR, also known as strong sync) solution based on the MySQL protocol, when a request is initiated at the application layer, only after a replica node successfully returns a message can the source node respond to the application layer with a request success, ensuring that the source and replica nodes have the same data.
When you perform strong sync replication, the source database will be hanged if it is disconnected from the replica database or if the replica database fails. If there is only one source or replica database, the high-availability solution will be unavailable, because if only one single server is used, part of the data will be lost completely when a failure occurs, which does not meet the requirements for finance-level data security.
Therefore, based on MAR, TDSQL for MySQL provides a downgradable strong sync scheme, which is similar to the semi-sync technology of Google but has a different implementation scheme.
In addition, TDSQL for MySQL MAR parallelizes the serial sync threads and introduces the worker thread capabilities, which greatly improve the performance. In the same cross-AZ (IDC with a latency of around 10–20 ms) test, the technical performance of MAR is around 5 times that of semi-sync replication on MySQL 5.6 and 1.5 times that of MariaDB Galera Cluster. In OLTP RW (mix read/write in source/replica architecture), its performance is 1.2 times that of async replication on MySQL 5.7. The comparison of the specific performance tested by the Intel® technical team is as shown below:
In production systems, high availability solutions are often required to ensure uninterrupted system operations. As the core of system data storage and services, the availability requirement for the database is higher than that for computing service resources.
The high availability solution of TDSQL for MySQL works by allowing the collaboration of multiple database services. In this way, if a database fails, another server will immediately take over its tasks, so the service will not be interrupted or be interrupted only for a very short period of time. This solution is also called source/replica high availability.
Based on the general source/replica high availability, TDSQL for MySQL further supports the following advanced features:
All TDSQL for MySQL shards support the MAR-based high availability scheme. If the source database fails, the system will automatically select the optimal replica database immediately to take over the tasks. The switch process is imperceptible to users, the access IP remains unchanged, and 24/7 continuous monitoring is provided for the databases and underlying physical devices.
If a failure occurs, the system will automatically restart the database and relevant processes. If a node crashes and cannot be recovered, it will be automatically rebuilt from its backup files, as shown below:
TDSQL for MySQL complies with applicable Chinese information security standards and has earned many Chinese and international certifications on behalf of TencentDB.
Security audit is one of the most important tracing methods; therefore, China's Cybersecurity Classified Protection Certification (Level 3) stipulates that an information system should support auditing. TDSQL for MySQL provides audit capabilities at the following three layers to deliver complete security protection:
- In public cloud, all security audit features are configured by default.
- In private cloud, system operation logging (Chitu system) is configured by default, while database SQL audit and server operation audit features are optional.
TDSQL for MySQL provides various open-source security solutions at the database kernel level, some of which have earned the recognition of the community. The following are some kernel security measures:
alter table ... drop partitioncommand, the database will not delete the tablespace file immediately. Instead, it will rename the file, gradually shrink it on the backend, and finally delete it. This feature can avoid system performance fluctuation caused by I/O load surges in the server's file system when a large tablespace file is deleted in one single request.
When you terminate your TDSQL instance, all data (including backup data) stored in it will be terminated. Tencent Cloud will not retain the data or actively restore your instance.
When deploying 1-DC disaster recovery, you should prevent the following failures for your database cluster:
Therefore, we recommend that you satisfy at least the following requirements for 1-DC disaster recovery deployment:
2-region-3-DC deployment is to add a disaster recovery center based on 1-region-2-DC deployment. The two disaster recovery instances are synced over a data communication network (DCN) to ensure data consistency.