Comparison Between DDS and On-Premises Databases

DDS provides high availability. It is more reliable, secure, and cost-effective than self-built databases.

**Table 1** Comparison between DDS and on-premises databases
Item	DDS	On-Premises Database
Service availability	99.95%	Requires setting up the primary/standby relationship and HA environment for ensuring the availability.
Data durability	99.99999999%	Requires self-guarantee, primary/standby relationship setup, and RAID setup.
System security	Anti-Distributed denial of service (DDoS) protection is provided, and system vulnerabilities are automatically addressed in a timely manner. Supports log auditing.	Requires procurement of expensive devices and software, as well as manual detection and fix of security vulnerabilities. Requires procurement of an audit system.
Database backup	Automated backup is supported. You can configure backup policies based on service requirements. You can create manual or physical backups at any time. DDS helps increase backup efficiency by 3 times. Backup files are automatically uploaded to Object Storage Service (OBS) for storage.	Requires self-setup and maintenance. The open-source version supports only logical backup, resulting in low backup efficiency.
Monitoring and alarm reporting	DDS interconnects with Cloud Eye, which provides a visualized platform for you to view monitoring metrics and set threshold alarms.	You have to purchase three servers and hosting fees can be expensive.
Hosting	There are no hosting fees.	Requires purchase of three servers and payment of high hosting fees.
Maintenance cost	There are no additional O&M costs, and second-by-second performance monitoring, threshold alarms, and event alarms can all be configured.	Requires large manpower investment and professional database administrator (DBA) for maintenance.
Deployment and scaling	Supports quick deployment, flexible application, elastic scaling, and one-click specification change.	Requires procurement, deployment, and coordination of hardware that matches original devices.
Log transfer	Stores slow query logs and error logs for one month.	Requires you to transfer, export, and query log information on your own.
High availability	Provides high availability capabilities, supporting second-level switchover and failover.	Requires self-setup of HA monitoring. Data may be lost after a manual primary/secondary switchover is performed using commands.