Backup data volume refers to the actual volume of the data that has been transmitted over the DBS server.
Common concepts
Database backup involves four concepts: database disk space, data file space, backup data volume, and storage data volume.
- Database disk space: refers to the disk space occupied by the database on the server. The database disk space consists of the data file space, log file space, operating system file space, and idle space. The database disk space of an ApsaraDB for RDS database is the storage space that you specified when purchasing the ApsaraDB for RDS instance. The database disk space of an ECS-hosted database is the sum of the system disk space and data disk space that you specified when purchasing the ECS instance.
- Data file space: refers to the disk space occupied by data files of the database on the server.
- Backup data volume: refers to the actual volume of the data that has been transmitted over the DBS server. The backup data volume depends on several factors such as the database type, backup method, and backup granularity.
- Storage data volume: refers to the volume of the data that is stored in the storage system. The storage data volume depends on several factors such as the backup data volume, backup data storage format, and compression algorithm.
- Space size ranking in the case of a single full backup: database disk space (ApsaraDB for RDS or ECS instance) > data file space (actually used space) > backup data volume (DBS) > storage data volume (OSS).
- Conclusion: You can reduce the backup data volume by modifying configuration items provided by DBS, such as the backup granularity and backup cycle, to reduce the DBS cost. You can use the compact storage format, compression methods, and automatic dumping and cleaning policies provided by DBS to reduce the storage data volume and the OSS cost in return.
