PolarDB provides complimentary access to the backup and restoration features. However, storage space is consumed by backup files. You are charged for backup storage that exceeds the free quota. This topic describes the billing rules for PolarDB backup storage that exceeds the free quota.
Billing rules for backup storage
Free quota
PolarDB offers a free storage quota for backup files. After this quota is exhausted, for single-region backup on PolarDB, you are charged based on the storage capacity and retention period of backup files (data and logs). For cross-region backup on PolarDB, you are charged based on the storage capacity and retention period of backup files (data and logs) and the network traffic consumed by cross-region backup.
Backup type | Free quota | |
Data backup | Level-1 backup | Database storage usage × 50% For information about how to view the database storage usage, see View the database storage usage. |
Level-2 backup | N/A | |
Log backup | 100 GB | |
You can enable the storage compression feature for clusters of PolarDB Enterprise Edition Cluster Edition. For more information, see Enable the storage compression feature.
The following rules related to the free quota of level-1 backups are applicable after you enable the storage compression feature. For more information about the free quota of level-1 backups for a cluster, see Billing rules for backup storage that exceeds the free quota.
If the storage of the cluster is billed by using the pay-as-you-go method, the free quota of level-1 backups after you enable the storage compression feature is calculated by using the following formula: Storage usage of the database before compression × 50%.
If the storage of the cluster uses the subscription billing method, the free quota of level-1 backups is calculated by using the following formula after you enable the storage compression feature: Max(Subscription-based storage capacity, storage usage of the database before compression) × 50%.
Example:
The storage of a cluster uses the subscription billing method, the subscription-based storage capacity of the cluster is 2 TB, and the storage usage of the cluster is 1.6 TB. After you enable the storage compression feature, the storage usage of the cluster is compressed to 0.5 TB. In this case, you can manually reduce the subscription-based storage capacity to 1 TB. For more information, see Manually scale up or scale down the storage capacity.
The free quota of level-1 backups for the cluster is 0.8 TB. The free quota is calculated by using the following formula: Max(1 TB, 1.6 TB) × 50% = 1.6 TB × 50% = 0.8 TB.
Billing
Storage types include level-1 backup, level-2 backup, and log backup based on backup types. Prices vary with different storage types.
The free storage quota for level-1 backup is database storage usage × 50%. After the free quota is exhausted, you are charged by PolarDB for the amount of additional storage space consumed by the backup and the length of time for which the backup is retained. The following table describes the prices.
Storage type
Region in the Chinese mainland
Region outside the Chinese mainland
Billing method
PSL5
USD 0.000464 per GB-hour
USD 0.000650 per GB-hour
Storage fee per hour = (Total size of level-1 backups - Free quota) × Unit price per hour
For example, a PolarDB cluster deployed in the Chinese mainland uses the PSL5 storage type. If the total size of level-1 backups (snapshots) is 700 GB and the database storage usage is 1,000 GB, the storage fee per hour is USD 0.0928.
The fee is calculated based on the following formula: [700 GB - (1,000 GB × 50%)] × USD 0.000464/GB = USD 0.0928.
NoteFor information about how to view the total size of level-1 backups, see FAQ.
PSL4
USD 0.0003 per GB-hour
USD 0.000433 per GB-hour
NoteAfter the free quota is consumed, you are charged for additional storage space on a pay-as-you-go basis. To reduce the costs of level-1 backup, we recommend that you use storage plans, which are cost-effective. For more information, see Billing rules for backup storage that exceeds the free quota.
No free storage quota is provided for level-2 backup. You can implement level-2 backup across different zones in the same region or across different regions.
Billing rules for intra-region level-2 backup
Intra-region level-2 backup is charged based on the size and retention period of the level-2 backup files.
Region in the Chinese mainland
China (Hong Kong) and regions outside China
Billing method
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Storage fee per hour = Total size of level-2 backups × Unit price per hour
For example, a PolarDB for MySQL cluster is deployed in the Chinese mainland. If the total size of level-2 backups is 1,000 GB, the storage fee per hour is USD 0.0325.
The fee is calculated based on the following formula: 1,000 GB × USD 0.0000325/GB = USD 0.0325.
Billing rules for cross-region level-2 backup
In addition to backup storage fees, cross-region data transfer fees are generated in cross-region level-2 backup.
Billable item
Region in the Chinese mainland
China (Hong Kong) and regions outside China
Billing method
Backup storage
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Storage fee per hour = Total size of level-2 backups × Unit price per hour + Cross-region data transfer fee
For example, a PolarDB cluster is deployed in the Chinese mainland. If the total size of level-2 backups is 1,000 GB and the amount of data transferred across regions is 500 MB, the storage fee per hour is USD 0.0691.
The fee is calculated based on the following formula: 1,000 GB × USD 0.0000325/GB + 500 MB/1024 × USD 0.075/GB = USD 0.0691.
Cross-region data transfer
For information about the cross-region data transfer fees, see Network traffic fees.
NoteCross-region level-2 backup is billed on a daily basis. In this example, daily prices are converted into hourly rates for convenience.
A free storage quota of 100 GB is provided for log backup. You can implement log backup across different zones in the same region or across different regions. After the free quota is exhausted, fees are generated for excess log storage usage.
Billing rules for intra-region log backup
After the free quota is exhausted, intra-region log backup is charged based on the size and retention period of the log backup files.
Region in the Chinese mainland
China (Hong Kong) and regions outside China
Billing method
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Storage fee per hour = (Total size of log backups - 100 GB) × Unit price per hour
For example, if the total size of log backups is 1,000 GB, the storage fee per hour is USD 0.02925.
The fee is calculated based on the following formula: (1,000 GB - 100 GB) × USD 0.0000325/GB = USD 0.02925.
Billing rules for cross-region log backup
In addition to the log backup storage fees, cross-region data transfer fees are generated in cross-region log backup.
Billable item
Region in the Chinese mainland
China (Hong Kong) and regions outside China
Billing method
Backup storage
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Storage fee per hour = (Total size of log backups - 100 GB) × Unit price per hour + cross-region data transfer fee
For example, a PolarDB cluster is deployed in the Chinese mainland. If the total size of log backups is 1,000 GB and the amount of data transferred across regions is 500 MB, the storage fee per hour is USD 0.0659.
The fee is calculated based on the following formula: (1,000 GB - 100 GB) × USD 0.0000325/GB + 500 MB/1024 × USD 0.075/GB = USD 0.0659
Cross-region data transfer
For information about the cross-region data transfer fees, see Network traffic fees.
NoteCross-region log backup is billed on a daily basis. In this example, daily prices are converted into hourly rates for convenience.
If you modify data after the snapshots are created for your cluster, the amount of snapshot backup increases. In this case, you are charged for the additional backup. If data is modified during defragmentation, the number of snapshot backup increases.
For example, if your database has 100 GB of data and you modify 10 GB of the data after a snapshot is created:
You are charged for 100 GB of data storage and 10 GB of snapshot storage.
If you choose to retain the snapshots when you delete your database, you are charged for 100 GB of snapshot storage.
Offset rules for storage plans
Use storage plans to offset level-1 backup storage fees
A storage plan can be used to offset the storage space exceeding the free quota for level-1 backups. If the capacity of the storage plan is insufficient to offset the level-1 backup storage space, you are charged for additional storage space on a pay-as-you-go basis.
The following table lists the ratios.
Region type | Offset ratio | Level-1 backup storage capacity offset by a 1-GB storage plan |
Region in the Chinese mainland (PSL4) | 0.41 | 1/0.41=2.44 GB |
Region in the Chinese mainland (PSL5) | 0.617 | 1/0.617=1.62 GB |
Region outside the Chinese mainland (PSL4) | 0.41 | 1/0.41=2.44 GB |
Region outside the Chinese mainland (PSL5) | 0.617 | 1/0.617=1.62 GB |
For example, you purchase a storage plan with a capacity of 100 GB and 50 GB is left after you offset the storage space (PSL5). Your cluster uses 50 GB of storage for level-1 backups (outside the free quota) in a Chinese mainland region. In this case, the storage plan automatically uses 31.25 GB (50/1.6=31.25) to offset the backup storage. As a result, the storage plan has 18.75 GB of capacity left.
If the remaining capacity of the storage plan is insufficient to offset the level-1 backups, you are charged for the excess storage usage on a pay-as-you-go basis.
For more information about storage plans, see FAQ about billing for storage plans.
Use storage plans to offset level-2 backup storage fees
A storage plan can be used to offset the storage space for level-2 backups. If the capacity of the storage plan is insufficient to offset the level-2 backup storage space, you are charged for additional storage space on a pay-as-you-go basis.
The following table lists the ratios.
Region type | Offset ratio | Level-2 backup storage capacity offset by a 1-GB storage plan |
Region in the Chinese mainland | 0.043 | 1/0.043=23.26 GB |
Region outside the Chinese mainland | 0.054 | 1/0.054=18.52 GB |
For example, you purchase a storage plan with a capacity of 100 GB, and 50 GB is left after it offsets the data storage usage. Your cluster uses 50 GB of storage for level-2 backups in a Chinese mainland region. In this case, the storage plan automatically uses 2.15 GB (50/23.26) to offset the backup storage usage and the storage plan has 47.85 GB of capacity left.
If the remaining capacity of the storage plan is insufficient to offset the level-2 backups, you are charged for the excess storage usage on a pay-as-you-go basis.
For more information about storage plans, see FAQ about billing for storage plans.
Use storage plans to offset log backup storage fees
A storage plan can be used to offset the storage space for log backups. If the capacity of the storage plan is insufficient to offset the log backup storage space, you are charged for additional storage space on a pay-as-you-go basis.
The following table lists the ratios.
Region type | Offset ratio | Log backup storage capacity offset by a 1-GB storage plan |
Region in the Chinese mainland | 0.043 | 1/0.043=23.26 GB |
Region outside the Chinese mainland | 0.054 | 1/0.054=18.52 GB |
For example, you purchase a storage plan with a capacity of 100 GB, and 50 GB is left after it offsets the data storage usage. Your cluster uses 50 GB of storage for log backups in a Chinese mainland region. In this case, the storage plan automatically uses 2.15 GB (50/23.26) to offset the backup storage usage and the storage plan has 47.85 GB of capacity left.
If the remaining capacity of the storage plan is insufficient to offset the log backups, you are charged for the excess storage usage on a pay-as-you-go basis.
For more information about storage plans, see FAQ about billing for storage plans.
Reduce the volume of backup data and the backup fee
Shorten the retention period of backup data based on your business requirements. For more information, see Configure backup settings.
Shorten the retention period of level-1 backups, for example, from 7 days to 3 days.
Shorten the retention period of level-2 backups, for example, from 70 days to 30 days.
NoteShortening the retention period of level-1 and level-2 backups poses risks. If the backup set that you want to use to restore data exceeds the retention period, you cannot restore data by using the backup set.
Shorten the retention period of log backups, for example, from 7 days to 3 days.
NoteShortening the retention period of log backups poses risks. If the log backup set that you want to use to restore data exceeds the retention period, you cannot restore data to a specific point in time.
Reduce the backup frequency (backup cycle) based on your business requirements. For more information, see Configure backup settings.
Reduce the frequency of level-1 backup, for example, from once a day to three times a week.
NoteReducing the frequency of level-1 backup may increase the amount of time required to restore data to a point in time.
Reduce the frequency of level-2 backup, for example, from three times per week to twice per week.
You can purchase storage plans to offset the fees of level-1 backup, level-2 backup, and log backup. For more information, see Storage plans.
Delete backup sets that you no longer require from the recycle bin of your cluster to reduce the costs of level-2 backup. For more information, see Delete a backup.