What is ApsaraDB How it work for RDS in Alibaba Cloud

Product overview
ApsaraDB for RDS (Relational Database Service) is a stable and reliable online database service,and it also supports elastic scaling function. Based on the Apsara distributed system and high- performance storage, RDS supports MySQL, SQL Server, and PostgreSQL engines. It provides a complete set of solutions for backup, recovery, monitoring, migration, disaster recovery, and troubleshooting database operation and maintenance.

ApsaraDB for MySQL
MySQL is the world’s most popular open source database. It is used in a variety of applications and is an important part of LAMP, a combination of open source software (Linux + Apache + MySQL + Perl/PHP/Python).
Two popular Web 2.0-era technologies that are built on MySQL-based architecture are the BBS software system Discuz, and blogging platform Wordpress. More recently, leading Internet companies including Alibaba, Facebook, and Google have all taken advantage of the flexibility of MySQL to build their mature database clusters.
Based on Alibaba’s MySQL source code branch, ApsaraDB for MySQL has proven to have excellent performance and throughput. It has withstood the massive data traffic and high number of concurrent users during many November 11 (Singles’ Day) shopping festivals - the Chinese equivalent of Cyber Monday. ApsaraDB for MySQL also provides a range of advanced functions including optimized read/write splitting, data compression, and intelligent optimization.
RDS for MySQL currently supports versions 5.5, 5.6 and 5.7. For specific support details, refer to the Quick Start guide of your corresponding MySQL version.

ApsaraDB for SQL Server
SQL Server was one of the first commercial databases and is an important part of the Windows platform (IIS + .NET + SQL Server), with support for a wide range of enterprise applications. The SQL Server Management Studio software comes with a rich set of built-in graphical tools and script editors.
Powered by high-availability architecture and anytime data recovery capabilities, ApsaraDB for SQL

Server provides strong support for a variety of enterprise applications. It also covers Microsoft’s licensing fee without any additional cost required.
RDS for SQL Server currently supports the 2008 R2 and 2012 versions.

ApsaraDB for PostgreSQL
PostgreSQL is the world’s most advanced open source database. Originally an academic relational database management system, its full compliance with SQL specifications, and robust support for a diverse range of data formats (including JSON as well as IP and geometric data, which are not supported by most commercial databases) is what sets PostgreSQL apart.
Apsara DB for PostgreSQL supports a range of features including transactions, subqueries, Multi- Version Concurrency Control (MVCC), and data integrity verification. It also integrates a number of important functions, including high availability and backup recovery, to help mitigate your operation and maintenance burden.
RDS for PostgreSQL currently supports version 9.4.

ApsaraDB for PPAS
Postgres Plus Advanced Server (PPAS) is a stable, secure, and scalable enterprise-level relational database. Based on PostgreSQL, PPAS delivers enhanced performance, application solutions, and compatibility, and provides the ability to run Oracle applications directly. It is a reliable and cost- effective option for running a variety of enterprise applications.
ApsaraDB for PPAS incorporates a number of advanced functions including account management, resource monitoring, backup recovery, and security controls, and it continues to be updated and improved regularly.
RDS for PPAS currently supports version 9.3.

Product Strengths
Low-cost and streamlined deployment
Simple deployment

You can customize RDS specifications through Alibaba Cloud’s official website or the API. After the order is confirmed, RDS generates the specified instance instantly.
RDS can work with ECS to reduce the application response time and save on public traffic fees.

On-demand upgrades
Initially, you can purchase an RDS instance that meets the existing business requirements. When requirements on the database and data storage capacity change, you can flexibly adjust the instance specifications without any interruptions to the service.

Effortless migration
RDS is used similarly to the native database engine, meaning that pre-existing knowledge and skills can transfer over to RDS management. Data can be migrated to RDS using the commercial off-the- shelf data import and export tools with minimal labor required.

Ease of management
Alibaba Cloud is responsible for ensuring the normal operation of RDS through routine maintenance and management, such as hardware/software fault processing and database update patches. As a user, you can independently perform database addition, deletion, restart, backup, recovery and other management operations through the Alibaba Cloud console.

High performance
Parameter optimization
Alibaba Cloud has accumulated years of experience in production and optimization by gathering key opinions from top database experts in China and aggregating performance data on all the RDS instances. DBA continuously manages RDS over its lifecycle to ensure that RDS is running at optimal performance.

SQL optimization
Based on your application scenario, RDS will lock low-efficiency SQL statements and provide recommendations for optimizing your business code.

High-end backend hardware
All servers used by RDS have undergone multiple levels of service verification by multiple parties to ensure the exceptional performance and stability.

High security
Anti-DDoS attack
Notice: It is recommended that RDS instances are accessed over the Intranet in order to avoid DDoS attacks.

When Internet connection is used to access RDS instances, a risk of DDoS attacks occurring on the network is possible. If this occurs, the RDS security system initiates flow cleaning. If the attack reaches the black hole threshold or the flow cleaning operation fails, black hole processing will be triggered.
The following describes how flow cleaning and black hole processing work and when they are triggered:

Flow cleaning:

This applies only to inbound traffic from the Internet. During this process, the RDS instance can be normally accessed. Flow cleaning is triggered if a single ApsaraDB instance meets any of the following conditions:

Package Per Second (PPS) reaches 30,000.

Bits Per Second (BPS) reaches 180 Mbps.

The number of concurrent connections created per second reaches 10,000.

The number of concurrent active connections reaches 10,000. The number of concurrent inactive connections reaches 10,000.
The system automatically triggers and terminates flow cleaning.

Black hole processing:
This only applies to inbound traffic from the Internet. Black hole processing ensures security of the overall RDS service by blocking malicious attacks. During this process, RDS instances and their services cannot be accessed from the Internet.
Black hole processing will trigger if the following conditions are met:

BPS reaches 2 Gbps.
Flow cleaning is ineffective.

The black hole will be removed automatically after 2.5 hours.

Access control policy

You can define the IP addresses that are allowed to access RDS. IP addresses that have not been specified will be denied access.
Each account can only view and operate its own database.

System security
RDS is protected by multiple firewall layers that can effectively block a variety of malicious attacks and ensure data security.
Direct login to the RDS server is not allowed. Only the port required by the specific database service is open.
The RDS server cannot initiate an external connection. It can only accept access requests.

Professional support team
Alibaba Group’s security department personnel provide rapid security technology support for RDS.

High reliability
Hot standby
RDS uses hot standby, so if a physical server fails, the service is switched over in seconds without

interruptions to application services.

Multi-copy redundancy
The data on the RDS server is stored on RAID, and backed up on OSS.

Data backup
RDS provides an automatic backup mechanism. You can set a backup schedule or initiate a temporary backup at any time.

Data recovery
Data can be recovered from a backup. Generally, data can be recovered within 7 days to a temporary RDS instance. After the data is verified, the data can be migrated back to the master RDS instance.

System Architecture
Data link service
ApsaraDB provides all of the data link services, including DNS, SLB, and Proxy. Since RDS uses the NativeDB Engine, and database operations are highly similar across engines, there is essentially no learning curve for users who are familiar with these data link services.

The DNS module supports the dynamic resolution of domain names to IP addresses, to prevent IP address changes from affecting the performance of ApsaraDB instances. After its domain name has been configured in the connection pool, an ApsaraDB instance can continue to be accessed even if the corresponding IP address changes.
For example, the domain name of an ApsaraDB instance is test.rds.aliyun.com, and the IP address corresponding to this domain name is If either test.rds.aliyun.com or is configured in the connection pool of a program, the instance can be accessed.
After performing a zone migration or version upgrade for this ApsaraDB instance, the IP address may change to If the domain name configured in the connection pool is test.rds.aliyun.com,

the instance can still be accessed. However, if the IP address configured in the connection pool is, the instance will no longer be accessible.

The SLB module provides instance IP addresses (including both intranet and Internet IP addresses) to prevent physical server changes from affecting the performance of RDS instances.
For example, the intranet IP address of an RDS instance is, and the corresponding Proxy or DB Engine runs on Normally, the SLB module redirects all traffic destined for to If fails, another address in hot standby status,, takes over for In this case, the SLB module will redirect all traffic destined for to, and the RDS instance will continue to provide its services normally.

The Proxy module performs a number of functions including data routing, traffic detection, and session holding.

Data routing: This supports distributed complex query aggregation for big data and provides the corresponding capacity management.

Traffic detection: This reduces SQL injection risks and supports SQL log backtracking when necessary.