Alibaba Cloud PolarDB: 5 Stages of Cloud Database Adoption

https://www.alibabacloud.com/blog/alibaba-cloud-polardb-5-stages-of-cloud-database-adoption_594253?spm=a2c65.11461447.0.0.1ada5a5cfk2wOd



First stage: cloud databases based on VMs and local SSDs
--> incurs higher costs due to an additional server and doubled data volume.



Second stage: high-availability cloud databases
 active-standby architecture enables HA with the percentage of service uptime up to 99.95%.incurs higher costs due to an additional server and doubled data volume.



(Improved Database Design to Cope with Increasing Loads)
Third stage: High-availability cloud databases with a read/write splitting architecture
The read/write splitting architecture is designed for databases where read to write ratio is higher than 3:1, with some at 10:1 and even higher. costs increase along with enhanced data processing capability. Since there are one primary instance, N read-only databases, and two standby databases, the system has N+1+2 copies of data. In addition, restricted by the local storage of physical servers, the maximum data volume is limited from 2 to 3 TB.


Fourth stage: High-availability read/write splitting databases based on shared storage


This architecture enables 3 data copies and increases data reliability. The data sharing model eliminates the need of read-only databases from data replication, enhancing system performance significantly. In addition, up to 15 read-only databases are supported with lower data latency. When only one read-only database is created, the read/write splitting feature is supported and the read performance is doubled. The cloud-native POLARDB is developed on the basis of the active-active HA architecture, which can meet the needs of over 80% of users in relational data scenarios.