Disk Types

Huawei Cloud provides various storage products for your BMSs, including block storage based on the distributed storage architecture, dedicated storage based on enterprise storage architecture, and local disks.

Block storage refers to EVS disks, which are block-based storage products and adopt a three-copy distributed mechanism. EVS disks provide high reliability, performance, and scalability. You can create or release them at any time.
Dedicated Distributed Storage Service (DSS) provides dedicated physical storage resources and adopts a three-copy distributed mechanism similar to block storage. It provides high availability and durability, and stable and low latency using multiple technologies, such as data redundancy and cache acceleration.
Local disks include NVMe SSDs, SATA disks, and others. They provide a low latency, high throughput, and high cost-effectiveness and are applicable to scenarios that have large volumes of data and require high storage I/O performance and real-time performance.
Because local disks of a single physical server may encounter a single point of failure (SPOF), you are advised to configure data redundancy at the application layer to ensure data availability.

**Table 1** Comparison of storage products
Storage Product	Storage Type	Typical Application Scenarios	Process
Block storage	Shared storage pools	Enterprise daily work Development and testing Enterprise applications, including SAP, Microsoft Exchange, and Microsoft SharePoint Distributed file systems Various databases, including MongoDB, Oracle, SQL Server, MySQL, and PostgreSQL	Create a disk and then attach the disk to the BMS.
DSS	Physically isolated storage pools and dedicated resources	Hybrid load: DSS supports hybrid deployment of HPC, database, email, OA, and web applications. High-performance computing OLAP applications	DSS can be used with BMSs in DeCs or those not in DeCs. DeC scenario: Enable DeC, apply for a storage pool, create a disk in the storage pool, and attach the disk to the BMS. Non-DeC scenario: Apply for a storage pool, create a disk in the storage pool, and attach the disk to the BMS.
Local disks	Local disks of servers	Big data Distributed cache	Create a BMS and use its local disks directly.