Cloud Block Storage

A cloud disk can be freely mounted and unmounted in the same region without the need to shut down or restart the server. Its storage capacity can be configured elastically and scaled on demand. Up to 20 cloud disks can be mounted to one single virtual machine, providing up to 320 TB of storage that fully satisfies the requirements of high-volume file systems in various businesses such as big data, data warehousing and log processing.

A snapshot is a full copy of a cloud disk that includes an image of the disk at the point in time when the copy starts and is stored in multiple availability zones in a redundant manner. It can be used to protect data security and availability in the event of faulty operations, attacks or tampering.
CBS uses the copy-on-write (CoW) strategy to make the snapshot, eliminating the concern over business interruption caused by reduced disk performance during snapshot creation. In addition, automatic snapshot creation can be set up based on the business characteristics to back up the business data stored in blocks. If data loss or inconsistency occurs due to faulty operations, attacks or tampering, rollback can be performed for the snapshot to restore the data to the business status at the point in time of the snapshot. Plus, snapshot enables you to quickly copy data to a new server for rapid batch deployment or business migration. In the gaming industry, snapshots can be used to create CBS volumes for quick deployment in dozens of service areas, fully sustaining high numbers of requests during day 1 server launch for public trial and greatly reducing the labor costs for OPS.

With CBS, data is automatically stored in three cross-rack copies in an availability zone, ensuring that any single point of disk failure will not affect the reliability of the data. For the purpose of cross-resource pool disaster recovery, Tencent Cloud has isolated the CBS system and the snapshot system by deploying them in different data centers. Additionally, the system cannot be accessed from public networks, completely blocking malicious attacks. In the same data center, CBS data and snapshot data are stored in different racks, eliminating the possibility of business interruption due to power or ventilation failure of any single rack. Even in extreme cases where all the redundant copies of data in the CBS system are lost, it is guaranteed that the data can be recovered from the snapshot system.

CBS is pay-as-you-go. In this flexible billing mode, CBS volumes can be activated/terminated at any time and charged based on the actual usage. Billing is on a per second level and charged hourly, making it especially suitable for scenarios such as ecommerce flash-sales where business needs can significantly fluctuate instantaneously.