Pricing Details

HUAWEI CLOUD Document Database Service (DDS) provides different DB instance types, including replica set and cluster. These instances are billed on a pay-per-use basis and there are no minimum usage requirements.

Pricing

**Table 1** Description
Item	Description	Billing Standards
Instance specifications	The instance specifications that you select. For a cluster instance, the mongos, shard, and config nodes are billed based on their specifications.	You can use the DDS price calculator to quickly obtain an estimate price of a DB instance with the specifications you select.
Storage	Storage space is billed based on the capacity you select. For cluster instances, the storage fees include the storage fees of shard and config nodes.
Backup storage (optional)	DDS backup files are stored in OBS and do not occupy the storage of DDS instances. DDS provides backup storage up to 100% of your provisioned database storage at no additional fees. If the backup storage usage exceeds 100% of your provisioned database storage, you will be charged for resource usage.
Audit log space (optional)	An audit log records operations performed on your databases and collections. The generated log files are stored in OBS.	Enabling audit log incurs certain fees.
(Optional) Public network traffic	DDS instances can be accessed from the Internet, and traffic fees are generated accordingly. You are not charged for the traffic generated in the cloud.	-

Billing Mode

DDS provides two billing modes: pay-per-use and yearly/monthly. Pay-per-use is recommended if you are unsure of your future service needs and want to avoid paying for unused resources. However, if you are sure of your needs, yearly/monthly will be less expensive.

Yearly/Monthly is a prepaid billing mode, which provides a larger discount than pay-per-use billing and is recommended for long-term use of resources.
Pay-per-use (hourly): This billing mode is flexible. You pay only for what you use. Pricing is listed on a per-hour basis, but bills are calculated based on the actual usage duration.
You can change the billing mode from pay-per-use to yearly/monthly or vice versa.
For operation details, see Changing the Billing Mode from Pay-per-Use to Yearly/Monthly and Changing the Billing Mode from Yearly/Monthly to Pay-per-Use.

Configuration Changes

You can change the specifications of an existing DB instance based on your service requirements. After the change, the instance is billed based on the new specifications.

Adding instances or nodes: You can add instances to handle growing services. After the instances are added, you will be charged based on the new number of instances. The number of cluster instances can only be increased. The number of mongos nodes ranges from 2 to 32, the number of shard nodes ranges from 2 to 32, and the number of config nodes is 1 by default.
Scaling up storage space: You can change the storage space based on service requirements. After scaling the storage space, you will be charged based on the new storage space. Note that storage space cannot be scaled down.

Renewal

DDS supports both yearly/monthly and pay-per-use billing modes.

Pay-per-use: You are charged for a full hour regardless of whether you use the full or partial hour. You can use the service as long as your account balance is sufficient. If your account balance is insufficient, the service cannot be used normally. Top up your account in a timely manner.
Yearly/monthly: An upfront payment is required when you purchase the service. No additional fees are incurred during your usage.

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