PolarDB:Configure backup policy settings

PolarDB for MySQL automatically enables both data backup and log backup for every cluster. These backups cannot be disabled. However, you can adjust the backup policy for a cluster to match your business requirements while maintaining data reliability.

PolarDB uses a tiered backup architecture:

• Level-1 backups are stored locally and provide fast data restoration. All storage classes support level-1 backups.

• Level-2 backups are stored remotely for long-term retention and disaster recovery. Only PSL4/PSL5 storage classes support level-2 backups.

Depending on your needs, you can customize the backup policy in the following ways:

• Change the level-1 backup method from Standard Backup to High-frequency Backup. This shortens the backup interval, increases backup frequency, and improves data restoration speed.

• Enable Cross-region Backup for level-2 backups to minimize data loss caused by natural disasters or hardware failures. Cross-region backup provides high availability for data restoration and meets requirements for data reliability, security, geo-redundant recovery, disaster recovery, long-term data archiving, and regulatory compliance.

Procedure

1. Log on to the PolarDB console. Select the region where the cluster is located. On the Clusters page, click the ID of the target cluster. In the navigation pane on the left, choose Settings and Management > Backup and Restoration.

2. On the Backup Policy Settings page, click Modify to configure the parameters. The available parameters vary based on the storage class, as described in the following sections.

Note

For more information about the backup policy parameters, see Data backup policy, Log backup policy, and General backup policy.

PSL4/PSL5

Data backups are categorized as level-1 or level-2 backups depending on their storage location. You can configure the Level-1 Backup, Level-2 Backup, Log Backup, and General parameters.

ESSD (PL0, PL1, PL2, PL3, and AutoPL)

Data backups can be saved only locally. They are also called level-1 backups. You can configure the Level-1 Backup, Log Backup, and General parameters.

Backup policy parameters

Quick reference

The following table summarizes the key defaults and ranges for backup policy parameters.

Parameter	Default	Range	Applies to
Backup Method (Level-1)	Standard Backup	Standard Backup or High-frequency Backup	All storage classes
Backup Cycle (Standard)	Once a day (PSL4/PSL5); Mon-Fri (ESSD)	Any days, minimum twice a week	All storage classes
Backup Frequency (High-frequency)	--	Every 2, 3, or 4 hours	All storage classes
Backup Retention Period (Level-1)	7 days	3--14 days	All storage classes
Backup Switch (Level-2)	Disabled	Enabled / Disabled	PSL4/PSL5 only
Same-region Backup Retention (Level-2)	--	30--7,300 days or long-term	PSL4/PSL5 only
Cross-region Backup Retention (Level-2)	--	30--7,300 days or long-term	PSL4/PSL5 only
Log Backup Retention (Same-region)	--	3--7,300 days or long-term	All storage classes
Log Backup Retention (Cross-region)	--	3--7,300 days or long-term	PSL4/PSL5 only

Data backup policy

Level-1 backup

Level-1 backup parameters are the same for all storage classes, except where noted.

Parameter	Description
Backup Method	The frequency of automatic backups. You can select Standard Backup or High-frequency Backup. See the descriptions below.
Backup Cycle	The days of the week to perform automatic data backups. This parameter is required only if you select Standard Backup (at specified intervals).
Backup Start Time	The time of day to start automatic data backups. This parameter is required only if you select Standard Backup (at specified intervals).
Backup Frequency	The interval for automatic data backups. This parameter is required only if you select High-frequency Backup. Options: Every 2 hours in the last 24 hours, Every 3 hours in the last 24 hours, Every 4 hours in the last 24 hours.
Backup Retention Period	The number of days to retain backups. Default: 7 days. Range: 3 to 14 days.

Standard Backup (at specified intervals)

• Default setting:

  • PSL4/PSL5: An automatic backup is performed once a day.

  • ESSD: An automatic backup is performed once a day from Monday to Friday.

• Custom options:

  • Backup Cycle: You can specify the days of the week to perform backups.

  • Backup Start Time: You can specify the time of day to perform backups.

• Security limit: To ensure data security, set the standard backup frequency to at least twice a week.

High-frequency Backup

• Provides enhanced protection by shortening the backup interval, increasing backup frequency, and improving data restoration speed.

• You can choose to perform a backup every 2, 3, or 4 hours within the last 24 hours.

• Backup retention rules:

  • Last 24 hours: All backup files completed within this period are retained.

  • Older than 24 hours: The system retains only the first backup file completed after 00:00 each day. Other backups are automatically deleted.

High-frequency backup example

Suppose you enable High-frequency Backup with the Create A Backup Every 4 Hours option at 08:00 on March 1. The system automatically creates the first backup within 4 hours (from 08:00 to 12:00 on March 1) and continues to create a backup every 4 hours after that.

Note

After you enable the High-frequency Backup feature, all backups completed within the last 24 hours are retained. For backups older than 24 hours, the system retains only the first backup completed after 00:00 each day. Other backups are deleted.

Snapshot at 16:00 on March 4

Date	Retained backups	Reason
March 4 (16:00--)	--	Future; no backups yet
March 3, 16:00 -- March 4, 16:00	All backups in this window	Within the last 24 hours
March 3	First backup completed after 00:00 (00:00--04:00)	Older than 24 hours; daily retention rule
March 2	First backup completed after 00:00 (00:00--04:00)	Older than 24 hours; daily retention rule
March 1	First backup completed (08:00--12:00)	First day; this is the earliest available backup

Snapshot at 20:00 on March 4 (four hours later)

Date	Retained backups	Reason
March 4 (20:00--)	--	Future; no backups yet
March 3, 20:00 -- March 4, 20:00	All backups in this window	Within the last 24 hours
March 3	First backup completed after 00:00 (00:00--04:00)	Older than 24 hours; daily retention rule
March 2	First backup completed after 00:00 (00:00--04:00)	Older than 24 hours; daily retention rule
March 1	First backup completed (08:00--12:00)	First day; this is the earliest available backup

Level-2 backup (PSL4/PSL5 only)

Parameter	Description
Backup Switch	Enable or disable level-2 backup. Level-2 backup is disabled by default.
Backup Method	You can select Same-region Backup or Cross-region Backup. After you enable level-2 backup, same-region backup is enabled by default.
Backup Cycle	The backup cycle for level-2 backups. You can select only the dates that correspond to level-1 backups.
Same-region Backup Retention	The retention period for same-region backups. Range: 30 to 7,300 days, or select Long-term Retain Backups before Cluster Deletion.
Cross-region Backup Region	The region where cross-region backups are stored.
Cross-region Backup Retention	The retention period for cross-region backups. Range: 30 to 7,300 days, or select Long-term Retain Backups before Cluster Deletion.

Note

• Enabling level-2 backup incurs additional fees. You cannot manually delete level-2 backups. You can adjust the retention period of level-2 backups to automatically delete them.

• If you enable both same-region backup and cross-region backup, two copies of backup data are created.

• If you cannot select cross-region backup, see Regions that support cross-region backup.

• Low-frequency level-2 backup: The backup cycle for level-2 backups is set to a lower frequency than that for level-1 backups. For example, if the level-1 backup cycle is five days a week and the level-2 backup cycle is three days a week, this is a low-frequency level-2 backup.

• Low-frequency replication rule: After you enable low-frequency level-2 backup, if you select a specific day for the backup cycle, the earliest backup set of that day is replicated to level-2 storage.

• After you enable low-frequency level-2 backup, subsequent backup sets can be replicated only if they meet the low-frequency replication rule.

• If you select Long-term Retain Backups before Cluster Deletion, you cannot set a retention period in days.

Log backup policy

Log backups are created by saving every database redo log file offline. The available log backup parameters vary based on the storage class.

PSL4/PSL5

Parameter	Description
Backup Method	You can select Same-region Backup or Cross-region Backup.
Same-region Backup Retention	The retention period for same-region log backups. Range: 3 to 7,300 days, or select Long-term Retain Backups before Cluster Deletion.
Cross-region Backup Region	This is the same as the cross-region backup region for level-2 backups. You do not need to select a region.
Cross-region Backup Retention	The retention period for cross-region log backups. Range: 3 to 7,300 days, or select Long-term Retain Backups before Cluster Deletion.

Note

• Same-region log backup is enabled by default and cannot be disabled.

• You can select cross-region backup for log backups only if cross-region backup is enabled for level-2 backups.

• Same-region and cross-region log backups cannot be deleted within their retention period.

• If you select Long-term Retain Backups before Cluster Deletion, you cannot set a retention period in days. Currently, only Enterprise Edition clusters support this option.

ESSD (PL0, PL1, PL2, PL3, and AutoPL)

Parameter	Description
Log Backup Retention	The retention period for log backups. Range: 3 to 7,300 days, or select Long-term Retain Backups before Cluster Deletion.

Note

• Log backups cannot be deleted within their retention period.

• If you select Long-term Retain Backups before Cluster Deletion, you cannot set a retention period in days. Currently, only Enterprise Edition clusters support this option.

General backup policy

The general backup policy defines how backup files are handled when a cluster is released.

Parameter	Description
When Cluster Is Deleted	The backup retention policy for when a cluster is deleted. Options: Retain all backups, Retain only the final backup, Delete all backups.

The following table describes each option.

Option	Behavior
Retain all backups	Retains all backups of the cluster when it is released. The system performs a full backup before the cluster is released to save all data.
Retain only the final backup	Performs a full backup before the cluster is released and retains only this backup.
Delete all backups	Immediately deletes all backups and logs after the cluster is released. This action cannot be undone.

Note

• If cross-region backup is configured and you select the Delete all backups policy, all cross-region backup sets and logs are deleted when the cluster is released. This action cannot be undone. If you select another policy, the configured expiration policy is executed.

• After a cluster is released, level-1 backups are automatically converted to level-2 backups. You can view all saved backups in the cluster recycle bin.

• After a cluster is released, the free quota is no longer available. You may be charged a small fee for retained backups. You can delete the backups of the released cluster at any time to save costs.