This topic describes how to enable PolarDB for PostgreSQL to automatically create backups at specified intervals or manually create backups to prevent data loss. PolarDB for PostgreSQL also allows you to retain backups of a cluster when you delete the cluster.

Pricing

The backup and restore features of Apsara PolarBD are free of charge. Only storage fees are charged. Fees are calculated based on the storage consumed by backups (cluster and log data) and the amount of time that the backups have been retained.

Note

Starting at 10:00 am on June 10, 2020 (Beijing Time), Alibaba Cloud begins charging for the backup feature of Apsara PolarBD.For more information, see [Notice] Alibaba Cloud begins charging for backups.

Table 1. Pricing
Region Level-1 backup Level-2 backup Log backup
Mainland China USD 0.000464/GB/hour USD 0.0000325/GB/hour USD 0.0000325/GB/hour
China (Hong Kong) and regions outside China USD 0.000650/GB/hour USD 0.0000455/GB/hour USD 0.0000455/GB/hour

Billing methods

Backup type Free quota Billing method
Level-1 backup Database storage usage × 50%

To check the database storage usage, log on to the Apsara for PolarDB console, and click the cluster name to navigate to the Overview page.

Storage fee per hour = (The total physical storage of level-1 backups - Free quota) × Unit price per hour
  • You can use level-1 backups for free if the physical storage of the level-1 backups is less than 50% of database storage usage.
  • For more information about the unit price per hour, see #table_5nf_txj_md0.
  • Section 1 in the following figure displays the total physical storage of the level-1 backups. Section 2 displays the total logical storage of the level-1 backups.Total physical storage of level-1 backups

For example, if the total physical storage of the level-1 backups is 700 GB and database storage usage is 1,000 GB, the storage fee per hour is USD 0.6.

The fee is calculated based on the following formula: [700 GB - (1,000 GB × 50%)] × USD 0.000464 = USD 0.0928

Level-2 backup None Storage fee per hour = The total physical storage of level-2 backups × Unit price per hour

For example: The total physical storage of level-2 backups is 1,000 GB. The storage fee per hour is USD 0.21.

The fee is calculated based on the following formula: 1,000 GB × USD 0.0000325 = USD 0.0325

Log backup 100 GB Storage fee per hour = (The total physical storage of log backups - 100 GB) × Unit price per hour

For example: The total physical storage of log backups is 1,000 GB. The storage fee per hour is USD 0.189.

The fee is calculated based on the following formula: (1,000 GB - 100 GB) × USD 0.0000325 = USD 0.02925

Backup methods

Backup method Description
System backup (Auto)
  • By default, automatic backup is performed once a day. You can configure the start time and backup cycle for automatic backup. For more information, see #section_ebx_rpf_v2b.
  • Automatically created backup files cannot be deleted.
Note To ensure data security, automatic backup must be performed at least twice a week.
Manual backup
  • You can manually back up data at any time. You can create up to three backups for a cluster. For more information, see #section_gzn_byx_ydb.
  • Manually created backup files can be deleted.

Configure automatic backup

  1. Log on to the PolarDB console.
  2. On the top of the page, select the region where the target cluster is located.
  3. Find the target cluster and click the cluster ID to go to the Overview page.
  4. In the left-side navigation pane, choose Settings and Management > Backup and Restore.
  5. Click Backup Settings.
    Backup settings
  6. In the dialog box that appears, configure parameters as follows.
    Backup settings-1
    Parameter Description
    Backup Method The default value Snapshot Backup is used and cannot be changed.
    Backup Cycle Set the backup cycle.
    Note To ensure data security, automatic backup must be performed at least twice a week.
    Start Time Set the start time for automatic backup.
    Level-1 Backups Retained For Set the retention period for level-1 backups.
    Note The retention period for level-1 backups is from 7 to 14 days.
    Level-2 Backup Enable or disable level-2 backup.
    Note By default, level-2 backup is disabled.
    Level-2 Backups Retained For Set the retention period for level-2 backups.
    Note
    • The retention period for level-2 backups is from 30 to 7,300 days.
    • To store level-2 backups permanently, you can select Retained Before Cluster Is Deleted. Then, you cannot set the retention period.
    Log Backups Retained For Set the retention period for log backups.
    Note
    • The retention period for log backups is from 7 to 7,300 days.
    • To save log backups permanently, you can select Retained Before Cluster Is Deleted. Then, you cannot set the retention period.
    When Cluster Is Deleted Set the backup retention policy that applies when you delete a cluster.
    • Retain All Backups Permanently: saves all backups when you delete a cluster.
    • Retain Last Automatic Backup Permanently: saves the latest backup when you delete a cluster.
    • Delete All Backups Immediately: does not save any backup when you delete a cluster.
    Note
    • If you choose the Retain All Backups Permanently or Retain Last Automatic Backup Permanently policy, the system will run an automatic backup task to save all data when you delete a cluster.
    • After you delete a cluster, level-1 backups will be automatically archived to level-2 backups. You can go to the Cluster Recycle page to view stored backups. For more information, see Cluster recycle bin.
  7. Click OK.

Manually create a backup

  1. Log on to the PolarDB console.
  2. On the top of the page, select the region where the target cluster is located.
  3. Find the target cluster and click the cluster ID to go to the Overview page.
  4. In the left-side navigation pane, choose Settings and Management > Backup and Restore.
  5. On the Backups tab, click Create Backup.
    Create backup
  6. In the Create Backup message that appears, click OK.
    Note You can create up to three backups for a cluster.

Restore data

For more information, see Restore data.

FAQ

  • Does the total physical storage of level-1 backups equal the sum of all backups?
    The total physical storage of level-1 backups does not equal the sum of all backups. The total physical storage of level-1 backups is displayed in the ① section, as shown in the following figure.The total physical storage of level-1 backups
  • Why is the total physical storage of level-1 backups smaller than the size of a single backup?

    Level-1 backups in Apsara PolarDB are measured by using two methods: the physical storage of all backups and the logical storage of each backup. Apsara PolarDB uses snapshot chains to store level-1 backups. Each data block is replicated only once. Therefore, the physical storage of all level-1 backups is smaller than the total logical storage of all level-1 backups, or sometimes even smaller than the logical storage of a single backup.

  • How are backups in Apsara PolarDB backup billed?

    Storage fees are charged for level-1 backups, level-2 backups, and log backups. By default, level-1 backup and log backup are enabled, but level-2 backup is disabled. Alibaba Cloud also offers free storage for level-1 backups and log backups.

  • What is the billing method of level-1 backups?

    Storage fee per hour = (Total physical storage of level-1 backups - Database storage usage x 50%) x Unit price per hour. For example, the total physical storage of level-1 backups of an Apsara PolarDB cluster is 700 GB and the database storage usage is 1,000 GB. Then, the storage fee per hour is calculated as (700 GB - 500 GB) × USD 0.000464/GB = USD 0.0928.

  • Can I use a storage plan to deduct the storage fee?

    No, a storage plan can only be used to deduct storage fees incurred by the stored data. It is not applicable to backups.

API reference

API Description
CreateBackup Creates a full snapshot backup for a specified PolarDB cluster.
DescribeBackups Queries the backup information of a specified PolarDB cluster.
DeleteBackup Deletes the backups of a PolarDB cluster.
DescribeBackupPolicy Queries the automatic backup policy of a specified PolarDB cluster.
ModifyBackupPolicy Modifies the automatic backup policy of a specified PolarDB cluster.