What types of redundant backup technologies are there for cloud storage?

There are several types of redundant backup technologies for cloud storage, each designed to ensure data durability and availability. Here are the main ones:

1. Replication: Data is copied and stored in multiple locations (e.g., different servers or data centers). This ensures that if one copy fails, others remain accessible.

   • Example: A file uploaded to cloud storage is automatically replicated across three different availability zones within the same region.

2. Erasure Coding (EC): Data is split into fragments, and additional parity fragments are generated. Even if some fragments are lost, the original data can be reconstructed.

   • Example: A 10TB dataset is split into 6 data fragments and 4 parity fragments. The system can recover the full dataset even if up to 4 fragments are lost.

3. RAID (Redundant Array of Independent Disks): Multiple physical disks are combined into a logical unit with redundancy, such as RAID 1 (mirroring) or RAID 5/6 (parity-based redundancy).

   • Example: A cloud storage provider uses RAID 6 to protect against the failure of two disks in an array.

4. Snapshotting: Periodic point-in-time copies of data are taken, allowing recovery from accidental deletions or corruption.

   • Example: A database in cloud storage is snapshotted daily, enabling restoration to a previous state if needed.

5. Multi-Region Replication: Data is replicated across geographically dispersed regions to protect against regional outages or disasters.

   • Example: A global enterprise stores its critical data in multiple Tencent Cloud regions (e.g., Beijing and Shanghai) for disaster recovery.

For cloud storage redundancy, Tencent Cloud offers services like COS (Cloud Object Storage) with built-in replication and cross-region replication features, as well as CBS (Cloud Block Storage) with RAID and snapshot capabilities. These ensure high durability and availability for stored data.