PolarDB allows you to use the backup and restoration features free of charge, but you are charged for the storage space occupied by backup files. PolarDB offers a free quota for backup storage. After this quota is exhausted, you are charged for backup storage based on the pay-as-you-go billing method. You can select a billing method from the guide section on the right side of the page to quickly view the billing rules for backup storage. PolarDB provides storage plans to help you reduce backup storage costs.
The following figure shows the backup policies for backup files. The backup policies vary based on the cluster edition. For more information about the billing rules, see the relevant sections of this topic.
Compared with Standard Edition, Enterprise Edition supports level-2 backups. The data of level-2 backups is completely derived from level-1 backups. Level-2 backups can be stored for an extended period of time with lower costs. However, data restorations from level-2 backups are relatively slow.
Free quota
PolarDB offers a free quota for backup storage. After the quota is exhausted, the billing rules for backup storage vary based on the Edition of the cluster.
Enterprise Edition
After the free quota for backup storage is exhausted, you are charged based on the size and the retention period of the backup files in intra-region backup scenarios. In cross-region backup scenarios, a cross-region network traffic fee is also generated in addition to the backup storage fee.
Backup type | Free quota |
Level-1 backup | Cluster storage usage × 50% For information about how to view the cluster storage usage, see View the database storage usage. |
Level-2 backup | None |
Log backup | 100 GB |
You can enable the storage compression feature for a PolarDB Enterprise Edition cluster. For more information, see Enable the storage compression feature. After you enable the storage compression feature, the following free quota rules apply to level-1 backup storage:
If the storage billing method of your cluster is pay-as-you-go, the free quota of level-1 backup storage is calculated by using the following formula after you enable the storage compression feature:
Cluster storage usage before compression × 50%.If the storage billing method of your cluster is subscription, the free quota of level-1 backup storage after you enable the storage compression feature is calculated by using the following formula:
Max (subscribed storage capacity, cluster storage usage before compression) × 50%.For example, the storage billing method of your cluster is subscription. The maximum storage capacity of the cluster is 2 TB, and the cluster storage usage is 1.6 TB. After you enable the storage compression feature, the cluster storage usage is reduced to 0.5 TB. Then, you manually reduce the storage capacity to 1 TB. For more information, see Manually scale down storage capacity. The free quota of level-1 backup storage can be calculated by using the following formula:
Max(1 TB, 1.6 TB) × 50% = 1.6 TB × 50% = 0.8 TB.
Standard Edition
After the free quota of backup storage is exhausted, you are charged based on the size and the retention period of the backup files.
Backup type | Free quota |
Data backup | Cluster storage usage × 50% For information about how to view the cluster storage usage, see View the database storage usage. |
Log backup | 100 GB |
Prices
Enterprise Edition
Level-1 backup
Storage type | Regions in the Chinese mainland | China (Hong Kong) and regions outside China | Hourly fee calculation method | |
PSL5 | Hot standby storage cluster enabled | USD 0.000464 per GB-hour | USD 0.000650 per GB-hour | Level-1 backup storage hourly fee = (Total size of level-1 backups - Free quota) × Unit price per hour |
Hot standby storage cluster disabled | ||||
PSL4 | Hot standby storage cluster enabled | USD 0.0003 per GB-hour | USD 0.000433 per GB-hour | |
Hot standby storage cluster disabled | ||||
Example: A 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 cluster storage usage is 1,000 GB, the hourly fee of level-1 backup storage is [700 GB - (1000 GB × 50% ) ] × USD 0.000464 per GB-hour = USD 0.0928 per hour.
For information about how to view the size of level-1 backups, see FAQ.
Level-2 backup and log backup
You can implement level-2 backup or log backup across different zones in the same region or across different regions. For backup across different zones in the same region, you are charged based on the size and retention period of the backup files. For backup across different regions, a cross-region network traffic fee is also generated in addition to the backup storage fee.
Intra-region backup
Backup type
Regions in the Chinese mainland
China (Hong Kong) and regions outside China
Hourly fee calculation method
Level-2 backup
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Level-2 backup storage hourly fee = Total size of level-2 backups × Unit price per hour
Log backup
Log backup storage hourly fee = (Total size of log backups - 100 GB) × Unit price per hour
Example 1: If the total size of level-2 backups of a cluster deployed in the Chinese mainland is 1000 GB, the hourly fee of level-2 backup storage is 1000 GB × USD 0.0000325 per GB-hour = USD 0.0325 per hour.
Example 2: If the total size of log backups of a cluster deployed in the Chinese mainland is 1000 GB, the hourly fee of log backup storage is (1000 GB-100 GB) × USD 0.0000325 per GB-hour = USD 0.02925 per hour.
Cross-region backup
Backup type
Billable item
Regions in the Chinese mainland
China (Hong Kong) and regions outside China
Hourly fee calculation method
Level-2 backup
Backup storage
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Level-2 backup storage fee per hour = Total size of level-2 backups × Unit price per hour + cross-region network traffic fee
Cross-region network traffic
For more information about the network traffic fees, see Network traffic fees.
Log backup
Backup storage
USD 0.0000325 per GB-hour
USD 0.0000455 per GB-hour
Log backup storage fee per hour = (Total size of log backups - 100 GB) × Unit price per hour + cross-region network traffic fee
Cross-region network traffic
For more information about cross-region network traffic fees, see Network traffic fees.
Example 1: A cross-region level-2 backup is performed between regions in the Chinese mainland. The total size of level-2 backups is 1000 GB, and the network traffic consumed for the cross-region backup is 500 MB. The hourly level-2 backup storage fee is 1000 GB × USD 0.0000325 per GB-hour + 500 MB/1024 × USD 0.075 per GB = USD 0.0691 per-hour.
Example 2: A cross-region log backup is performed between regions in the Chinese mainland. The total size of log backups is 1000 GB, and the network traffic consumed for the cross-region backup is 500 MB. The hourly log backup storage fee is (1000 GB - 100 GB) × USD 0.0000325 per GB-hour + 500 MB/1024 × USD 0.075 per GB = USD 0.0659 per hour.
NoteCross-region backup is billed on a daily basis. In this example, the daily prices are converted into hourly rates for convenience.
Fees for cross-region backup are recorded in DBS bills.
Standard Edition
Backup type | Regions in the Chinese mainland | China (Hong Kong) and regions outside China | Hourly fee calculation method |
Data backup | USD 0.00003231 per GB-hour | USD 0.00004523 per GB-hour | Data backup storage fee per hour = (Total size of data backups - Free quota) × Unit price per hour |
Log backup | USD 0.0000325029 per GB-hour | USD 0.0000455041 per GB-hour | Log backup storage hourly fee = (Total size of log backups - 100 GB) × Unit price per hour |
Example 1: A cluster is deployed in the Chinese mainland. The total size of data backups of the cluster is 700 GB, and the cluster storage usage is 1,000 GB. The hourly data backup storage fee is [700 GB - (1000 GB × 50% ) ] × USD 0.00003231 per GB-hour = USD 0.006462 per hour.
Example 2: A cluster is deployed in the Chinese mainland. The total size of log backups of the cluster is 1000 GB. The hourly log backup storage fee is (1000 GB-100 GB) × USD 0.00004523 per GB-hour =0.040707 per hour.
Storage plans
You can use storage plans to offset the storage usage of level-1 backups or data backups, level-2 backups, and log backups.
Storage plans can also be used to offset the cluster storage usage and cold data archiving storage usage.
Prices
The prices of storage plans vary based on the subscription duration and specifications. The larger the specifications and the longer the subscription duration, the more cost-effective the storage plan. For information about the prices of storage plans, see Prices.
Offset rules
A storage plans offsets the storage usage of level-1 backups, data backups, level-2 backups, and log backups at a fixed hourly quota. For example, if you purchase a storage plan of 100 GB, you are entitled to a fixed quota of 100 GB per hour to offset the corresponding storage usage.
Enterprise Edition
Backup type | Offset factor | Storage usage offset by using a 1-GB storage plan | |||
Regions in the Chinese mainland | China (Hong Kong) and regions outside China | Regions in the Chinese mainland | China (Hong Kong) and regions outside China | ||
Level-1 backup | PSL5 | 0.617 | 1/0.617 = 1.62 GB | ||
PSL4 | 0.41 | 1/0.41 = 2.44 GB | |||
Level-2 backup | 0.043 | 0.054 | 1/0.043 = 23.26 GB | 1/0.054 = 18.52 GB | |
Log backup | |||||
Standard Edition
Backup type | Offset factor | Storage usage offset by using a 1-GB storage plan | ||
Regions in the Chinese mainland | China (Hong Kong) and regions outside China | Regions in the Chinese mainland | China (Hong Kong) and regions outside China | |
Data backup | 0.043 | 0.054 | 1/0.043 = 23.26 GB | 1/0.054 = 18.52 GB |
Log backup | ||||
Example: Use a storage plan to offset the backup storage usage of the cluster beyond the free quota.
Your Alibaba Cloud account has a storage plan of 50 GB and the following PolarDB clusters:
Cluster name | Edition | Hot standby storage cluster enabled | Billing method (compute nodes) | Storage type | Storage billing method | Cluster storage usage | Level-1 backup/data backup storage usage | Level-2 backup storage usage | Log backup storage usage |
A | Cluster Edition | Yes | Subscription | PSL5 | Subscription | 2.76 GB (subscribed amount: 50.00 GB) | 322.00 MB (a free quota of approximately 25 GB) | 2.45 GB | 70 GB |
C | Cluster Edition | No | Pay-as-you-go | PSL5 | Pay-as-you-go | 100 GB | 3.21 GB (a free quota of approximately 50 GB) | 2.38 GB | 219 GB |
E | Standard Edition | No | Subscription | PL1 ESSD | Subscription | 2.38 GB (subscribed amount: 100.00 GB) | 480.00 MB (a free quota of approximately 50 GB) | No | 79 GB |
50 50-GB storage plan automatically offsets the storage usage of the clusters:
The storage plan offsets the backup storage usage based on the offset order. For more information about the offset order, see the "Offset order" section of this topic.
Level-1 backup storage usage beyond the free quota of Enterprise Edition clusters:
The level-1 backup storage usage of Cluster A does not exceed the free quota.
The level-1 backup storage usage of Cluster C does not exceed the free quota.
Level-2 backup storage usage of Enterprise Edition clusters:
Cluster A has a level-2 backup storage usage of 2.45 GB. An offset ratio of 0.043 is applied to the level-2 backup storage usage. As a result, 0.10535 GB (calculated as 2.45 GB × 0.043) of the storage plan is used to offset the level-2 backup storage usage of the cluster. Then, the storage plan has a remaining capacity of 49.89465 GB (calculated as 50 GB - 0.10535 GB).
Cluster C has a level-2 backup storage usage of 2.38 GB. An offset ratio of 0.043 is applied to the level-2 backup storage usage. As a result, 0.10234 (calculated as 2.38 GB × 0.043) of the storage plan is used to offset the level-2 backup storage usage of the cluster. Then, the storage plan has a remaining capacity of 49.79231 GB (calculated as 49.89465 GB - 0.10234 GB).
Log backup storage usage beyond the free quota of Enterprise Edition clusters:
The log backup storage usage of Cluster A does not exceed the free quota.
Cluster C has a log backup storage usage of 119 GB beyond the free quota (calculated as 219 GB - a free quota of 100 GB). An offset ratio of 0.043 is applied to the log backup storage usage. As a result, 5.117 GB (calculated as 119 GB × 0.043) of the storage plan is used to offset the log backup storage usage of the cluster. Then, the storage plan has a remaining capacity of 44.67531 GB (calculated as 49.79231 GB - 5.117 GB).
Data backup storage usage beyond the free quota of Standard Edition clusters:
The data backup storage usage of Cluster E does not exceed the free quota.
Log backup storage usage beyond the free quota of Standard Edition clusters:
The log backup storage usage of Cluster E does not exceed the free quota.
To sum up, a total of 5.32469 GB (calculated as 0.10535 GB + 0.10234 GB + 5.117 GB) of the storage plan is used to offset the backup storage usage beyond the free quota of the clusters. The storage plan has a remaining capacity of 44.67531 GB (50 GB - 5.32469 GB).
This example describes only how a storage plan offsets the storage usage of level-1 backups/data backups, level-2 backups, and log backups of the PolarDB clusters. Other types of storage usage, such as the cluster storage usage and cold data archiving storage usage, are not included in this example.
More
For more information about storage plans, see Storage plans.