Single Replica SSD Disk is a persistent block-level storage product offered by Tencent Cloud on its new generation of high-IO instance types (such as IA5se and IA3se; for details, see the relevant descriptions of instance types in the Instance Specifications document). Unlike CBS and local disks (for reference, see the relevant descriptions of some high-IO and big data instance types in the Instance Specifications document), a Single Replica SSD Disk is mapped over the network from a complete, remote physical disk to an instance. The instance has full and exclusive read/write access to it. Data is stored only on that physical disk, with no redundancy. CBS: a distributed storage service provided by Tencent Cloud. Data is automatically stored with multi-replica redundancy within an AZ, ensuring high data reliability. It is accessed over the network.
Local disk: the local instance storage on physical servers for some of Tencent Cloud's high-IO and big data instance types. It provides no data redundancy and is accessed via the bus.
Single Replica SSD: a remote physical disk provided by Tencent Cloud on its new generation of high-IO instance types (such as IA5se and IA3se; for details, see the relevant descriptions of instance types in the Instance Specifications document). It provides no data redundancy and is accessed over the network. Use Cases
I/O-intensive applications with application-layer high availability capabilities: For I/O-intensive applications such as large relational databases, NoSQL, and ElasticSearch that have low storage latency requirements, single-replica SSDs are recommended. However, you must be aware of the single point of failure risk. It is strongly recommended that you implement high availability at the business layer.
Big data services: big data processing services such as EMR, Spark, and CK that have data redundancy.
Lifecycle
The lifecycle of a Single Replica SSD is fully aligned with that of the CVM instance to which it is attached. This means a Single Replica SSD can only be purchased with specific CVM instances and is terminated when those instances are terminated.
Purchase
Single Replica SSDs can only be purchased together with specific CVM instances and cannot be purchased separately. For more information on purchasing CVMs, see instance creation. Product Features
The size of a Single Replica SSD is fixed and cannot be expanded or reduced.
The performance specifications for a Single Replica SSD are: sequential read/write throughput of 1 GB/s per disk (with a 128KB block size), random IOPS of 100,000 (with a 4KB block size), and read/write latency of approximately 0.08 ms.
Single Replica SSDs provide no data redundancy and pose risks of data loss. It is strongly recommended that you use Single Replica SSDs only within a high-availability architecture.
Single Replica SSDs do not support capabilities such as detachment, snapshot, data backup points, or type adjustment.
If a Single Replica SSD experiences an irreparable failure, we will notify you and request your authorization for subsequent operations.
Similarities and Differences Between Single Replica SSD and Instance Local Storage
|
No redundancy | No redundancy |
Physical hard drives on the local physical server | Remote physical hard drives |
Fixed in size and can only be purchased together with specific instance types. | Fixed in size and can only be purchased together with specific instance types. |
Cannot be migrated and requires waiting for downtime maintenance. | Instances can be migrated to other healthy physical servers. |
Cannot be migrated and requires waiting for downtime maintenance. | Data can be migrated to other healthy Single Replica SSD. |
Cannot be migrated, and data cannot be recovered. | Cannot be migrated, and data cannot be recovered. |