This topic describes how to view the free quota for backup storage of an ApsaraDB RDS for PostgreSQL instance. It also provides more information about how to calculate your excess backup storage usage. The free quota can vary based on the instance configuration.

Background information

Backup files occupy backup storage. Each RDS instance is allocated with a free quota for backup storage. If the total size of backup files exceeds the free quota, additional fees are incurred.

Formula

RDS instances that are equipped with standard or enhanced SSDs support only snapshot backups. The free quota that is provisioned to store snapshot backup files is calculated based on the following formula: Free quota = 200% × Storage capacity purchased during instance creation (unit: GB; rounded up to the next integer).

RDS instances that are equipped with local SSDs support only physical backups. The free quota that is provisioned to store physical backup files is calculated based on the following formula: Free quota = 50% × Storage capacity purchased during instance creation (unit: GB; rounded up to the next integer).

The excess backup storage usage for which you must pay an hourly rate is calculated based on the following formula: Excess backup storage usage = Size of data backup files + Size of log backup files - Free quota.

Assume that your RDS instance is equipped with local SSDs. If the size of data backup files is 30 GB, the size of log backup files is 10 GB, and the storage capacity purchased during instance creation is 60 GB, then the excess backup storage usage for which you must pay an hourly rate is 10 GB based on the following calculation: Excess backup storage usage = 30 + 10 - 50% × 60 = 10 (GB). This indicates that you must pay for an additional 10 GB of backup storage per hour.

Note The RDS Basic Edition that is used with some database engines supports a free-of-charge retention period of seven days. For more information, see the ApsaraDB for RDS console.

Procedure

  1. Visit the RDS instance list, select a region above, and click the target instance ID.
  2. In the Usage Statistics section at the lower part of the page, view the free quota for backup storage to the right of Backup Size.
    Note The free quota for backup storage can vary based on the instance configuration. The following figure only shows an example.
    免费额度

FAQ

  • Will backup files occupy the storage that I purchased during instance creation?

    No, backup files do not occupy the storage that you purchased during instance creation.

  • Can I purchase subscription-billed backup storage?

    No, you cannot purchase backup storage.