RDS: Seven Things You Have to Know
Created#More Posted time:Jul 14, 2016 14:07 PM
1. About RDS Instance Upgrading
The RDS instance will be unreachable for up to 30 seconds during an upgrade. You must set the program to reconnect to the RDS instance automatically to avoid service downtime.
2. Risks in Switching Over the RDS Connection Mode
The RDS will disconnect from the server during a switchover between intranet and Internet connection modes. After the switchover, you must promptly update the connection address in the program. Switching the connection mode will also cause a change of the IP address.
3. RDS Rollback Risks
Currently, RDS supports data rollback, but only for the entire instance, not for a single table or database. It is important to back up crucial data before the rollback to prevent data loss. Creating a temporary instance is suggested for recovering the data in some tables or data. You can import the required data back to the production databases from the temporary instance.
4. About RDS Locking Mechanism
RDS has a locking mechanism. If the storage space of your RDS instance is full, the system will lock your instance into read-only status. It is suggested that you regularly check the storage usage or enable the system to send a text message alert to the usage on the RDS console.
5. About RDS Failover
The RDS works in primary/standby mode to ensure high availability. If the primary database encounters a fault, the RDS will switch to the standby database within 30 seconds. The RDS will be unreachable for up to 30 seconds during the failover. You must set the program to reconnect to the RDS automatically to avoid service downtime.
6. About Data Synchronization Modes of RDS for MySQL
RDS for MySQL 5.1 synchronizes data between the primary and the standby databases in asynchronous mode. This mode gives a high performance but also a certain possibility that the data in the primary and standby databases is not completely consistent.
RDS for MySQL 5.5 synchronizes data between the primary and the standby databases in semi-synchronous mode. This mode decreases the write performance and greatly lowers the possibility of data inconsistency. In the case that the requirement for data reliability is high (for example, financial systems), it is suggested that you purchase RDS for MySQL version 5.5 or above.
7. I Have Purchased an RDS Instance. What Happens Now?
You do not need to conduct basic database O&M (such as high availability, backup, and security patch work). However, you must consider the following things:
1) Check whether the CPU, IOPS, storage space, and connection quantity are adequate for your RDS instance. If not, make optimization or upgrading.
2) Check whether your RDS instance performs well. Optimize the SQL statements if a large number of statements that slow the SQL appear. Check whether there are extra or missing indexes.
3) Check whether your RDS instance generates SQL injection warnings. If so, your databases may be vulnerable to SQL injection attacks and you must modify your application to prevent such attacks.