Document Database Service (DDS)
In addition to relational databases, those that follow a non-relational structure - also known as NoSQL databases - can also be used for the structured storage of data. A subcategory of these are so-called document-oriented databases, in which, as the name suggests, data is stored in the form of documents. This is particularly advantageous when a flexible data structure is required and complex, unstructured data needs to be browsed in the shortest possible time.
The Open Telekom Cloud also offers a document-oriented database: Our corresponding service is called Document Database Service (DDS). For this, we use the MongoDB platform. This is particularly suitable for database applications that require simple scalability, maximum availability and flexible adaptability.
DDS uses Virtual Private Clouds (VPCs) and network security groups to isolate your DB instances. A multi-layer network provides protection against various malicious attacks, while SSL is used to encrypt transmitted data.
The three-node replica set architecture of DDS ensures high service availability. If a primary node goes down or becomes faulty, a secondary node is automatically assigned to the primary role and continues normal operation. If a secondary node is unavailable, a hidden node will take the role of the secondary.
You can scale up the storage space based on your service requirements and only pay for the resources you consumed. If the storage space of the current DB instance cannot meet your application requirements, you can scale up the storage space based on your service requirements and only pay for the resources you consumed. During the expansion, your services will not be interrupted.
Data can be backed up automatically or manually, initiated at any time according to your service requirements. These backups can be used to restore DB instances in just a few clicks. You are able to set the backup retention period and modify the backup policy as you see fit. Backups are stored in Object Storage Service (OBS), improving the data disaster recovery capabilities while reducing the needed storage space.
Virtual Private Cloud (VPC) security groups can have rules that govern both inbound and outbound traffic of DB instances.
DDS monitors instance performance, reducing O&M activities by as much as 60%. It provides real-time monitoring information about CPU utilization, disk usage, IOPS, and number of active connections, allowing you to check instance status at any time.
Each mongos is a single node. To realize load balancing and automatic failover, you can provision multiple mongos. A single cluster supports 2 to 16 mongos.
Each shard is a three-node replica set. A single cluster supports 2 to 16 shards.
config is mandatory in a cluster instance. It stores instance configuration information and consists of one replica set.
mongos and shards cannot be added using native commands but can be scaled out on the DDS console.
You cannot connect to a config and shard. Data operations can only be delivered by connecting to mongos.
Currently, a three-node replica set cannot be directly upgraded to a cluster.
A replica set consists of three nodes: primary, secondary, and hidden. The three-node architecture is automatically set up, and the three nodes synchronize data with each other automatically to ensure data reliability.
- The primary node is used to read and write requests.
- The secondary node is used to read requests.
- The hidden node is used to back up data.
You can directly perform operations on the primary and secondary nodes. If a primary node goes down or becomes faulty, a secondary node is automatically assigned to the primary role and continues normal operation. If a secondary node is unavailable, a hidden node will take the role of the secondary to ensure high availability. The figure below shows the Replica Set architecture.
Replica Set supports multiple management and control tasks, such as creating instances, changing configurations, and backing up instances. The system flexibly controls and tracks tasks, and manages exceptions based on the operations delivered by users.
Replica Set collects performance monitoring information about DB instances, including basic metrics, storage space, access requests, and the number of operations.
Collects slow query logs and access control logs, recording DB instance running status.
Replica Set backs up DB instance data and uploads it to OBS buckets. Currently, DDS supports automated and manual backup. Automated backups are kept for seven days by default.
Mobile Apps and Maps
DDS supports two-dimensional space indexes for mobile applications (apps) and maps that have location query requests. In addition, the dynamic storage mode of DDS is suitable for storing heterogeneous data of multiple systems, meeting the requirements of this scenario.
Internet of Things (IoT) applications generate terabytes of data and have high requirements on data write performance and low requirements on data read performance. DDS provides high write performance and shard-based DB instances to meet IoT requirements.
Content Management Systems (CMS) have a large amount of data and queries, much of which is non-structured and diverse. DDS provides high-performance schema-free, GridFS, and shards to support CMS applications.
DDS provides schema-free to meet ever-changing requirements in the gaming industry, shortening R&D periods and reducing R&D costs.