Database Backup (DBS) allows you to back up your databases in a continuous and cost-effective manner. DBS provides a variety of backup schedule specifications, including micro, small, medium, large, and xlarge. More advanced backup schedule specifications offer lower unit prices and higher performance.This topic describes how to select a backup schedule specification.

Fees for backup schedule specifications

The free quota for data backup, unit price, and backup data and restoration performance vary with backup schedule specifications.

The following formula is used to calculate the fees for a backup schedule specification: Configuration fees + (Actual backup data size - Free quota for data backup) × Unit price of the backup schedule specification.

For example, a full backup is performed on a 50 GB database three times per week. The estimated size of backup data for the current month is 600 GB. The following section uses prices common in regions within mainland China to calculate fees for backup schedule specifications:
  • Fees for micro: CNY 30 + (600 GB - 40 GB) × CNY 0.75/GB = CNY 450
  • Fees for small: CNY 140 + (600 GB - 400 GB) × CNY 0.35/GB = CNY 210
  • Fees for medium are CNY 224. The actual backup data size is smaller than the free quota. No additional fees are incurred.
For more information, see Billing overview.

Performance of backup schedule specifications

  • The following table describes the backup performance of backup schedule specifications.
    Specification Estimated time taken to back up 100 GB of data
    micro 20 hours
    small 5 hours
    medium 2.5 hours
    large 1.5 hours
    xlarge 1 hour
  • For more information about restoration performance, see Backup and restoration performance tests.

Concepts

Database backup scenarios involve the following concepts: database disk space, data file size, backup data size, and storage data size.

Concept Description
Database disk space The total disk space of a database consists of the total space consumed by data files, logs, and operating system files as well as the available space of the operating system of the server where the database resides.
Note
  • For an ApsaraDB RDS instance, the storage space that you select when you purchase the instance is database disk space.
  • For a database hosted on an Elastic Compute Service (ECS) instance, the collective storage space of the system disks and data disks that you select when you purchase the ECS instance is database disk space.
Data file size The data file size of a database is equal to the amount of disk space occupied by database data files on the server where the database resides.
You can perform the following operations to view the data file size of a database:
  • To view the data file size of an ApsaraDB RDS instance, log on to the ApsaraDB RDS console. In the left-side navigation pane, click Instances. On the Instances page, find the instance and click Manage in the Actions column. In the left-side navigation pane of the page that appears, click Monitoring and Alerts. On the Monitoring tab of the Monitoring and Alerts page, click Data Usage below the Disk Space (MB) chart.
  • To view the data file size of a database hosted on a Linux server, go to the directory of the data files of the database and run the du -sh command.
  • To view the data file size of a database hosted on a Windows server, open the folder where the data files of the database reside. Right-click the blank area and select Properties.
Backup data size The backup data size of a database refers to the amount of data that you back up by using DBS. This size depends on a variety of factors such as the database type, backup mode, and backup granularity.
Storage data size The storage data size of a database refers to the amount of data stored in the storage system. This size depends on a variety of factors such as the backup data size, the storage format of backup data, and the compression algorithm.

The following space sizes are in descending order: database disk space > data file size > backup data size > storage data size.