A cloud disk is a highly available, reliable, low-cost, customizable network block device that can be used as an independent and scalable hard disk for CVM. It provides block-level data storage and uses a distributed mechanism with triple replicas and EC to ensure data reliability for the CVM. Different hard disk types vary in performance, features, and pricing. You can choose based on the requirements of your deployed applications.
- Premium Cloud Disk: Premium Cloud Disk is a hybrid storage type that provides high-performance storage capabilities close to solid-state storage through a cache mechanism. It uses a distributed mechanism with three replicas to ensure data reliability. Premium Cloud Disk is suitable for small-to-medium-sized application scenarios with high data reliability requirements and moderate performance requirements, such as Web/App servers, business logic processing, and small-to-medium website building.
- SSD: SSD is based on full NVMe SSD storage medium, uses a distributed mechanism with three replicas, and provides low latency, high random IOPS, high throughput I/O capacity, and data security up to 99.9999999%. Cloud SSD is suitable for scenarios with high I/O performance requirements.
The performance metrics of different types of cloud disk are as follows:
| Performance Metrics | SSD | Premium Cloud Disk |
|---|---|---|
| Maximum capacity per disk (GiB) | 32000 | 32000 |
| Maximum IOPS of a single disk | 26000 | 6000 |
| Calculation formula for random IOPS performance. | Maximum random IOPS = 1800 + Storage capacity (GiB) x 30 The maximum random IOPS shall not exceed 26000. |
Maximum random IOPS = 1800 + Storage capacity (GiB) × 8 The maximum random IOPS shall not exceed 6000. |
| Maximum throughput of a single disk (MB/s) | 260MB/s | 150MB/s |
| Calculation formula for throughput performance (MB/s) | Maximum throughput = 120 + Storage capacity (GiB) x 0.2 The maximum throughput shall not exceed 260 MB/s. |
Maximum throughput = 100 + Storage capacity (GiB) x 0.15 The maximum throughput shall not exceed 150 MB/s. |
| Single-channel random read/write latency | 0.5 - 3ms | 0.8 - 4ms |
The main difference between SSD and Premium Cloud Disk lies in I/O performance.
SSD is more suitable for scenarios with medium-to-large loads, for example:
- Medium and large database: It can support medium and large relational database applications such as MySQL.
- Image process: It can support data analysis and storage services such as image process.
Premium Cloud Disk mainly applies to the following data scenarios:
- It is suitable for small and medium databases, Web/App servers, etc., providing long-term stable I/O performance output.
- It is suitable for scenarios that require a balance between storage capacity and performance, such as enterprise office services.
- Meet the I/O requirements of core business testing and development and joint debugging environment.