Local Disk Overview
A local disk is a storage device that is located on the same physical server as a Cloud Virtual Machine (CVM) instance and has the characteristics of high reading and writing speed IO and low latency.
The local disk is a part of the local storage of the physical machine where the CVM instance is located. It is a storage area of the local storage of the physical machine where the CVM instance is located. The local disk is a part of a single physical machine. The data reliability depends on the reliability of the physical machine, and there is a risk of single point failure.
- When a hardware failure occurs on the physical machine where the instance is located, there is a risk of data loss on the local disk. We recommend that you perform data redundancy at the application layer to ensure data availability. If your application lacks a data reliability architecture design, we recommend using Cloud Block Storage (CBS) in your instances concurrently to improve data reliability.
- For Cloud Virtual Machines (CVMs) that only purchase local disks, hardware (CPU, memory, hard disk) upgrades are not supported, only bandwidth upgrades are supported.
- Currently, local disks can only be used as data disks for CVMs, such as high IO instances.
Applicable Scenario
- Distributed Applications: I/O intensive applications such as NoSQL, MPP data warehouse, and distributed file systems. These applications inherently have distributed data redundancy capabilities.
- Large Online Application Logs: Large online applications generate a significant amount of log data, requiring high-performance storage, while the reliability requirements for storing these logs are not as stringent.
Lifecycle
The lifecycle of a local disk is the same as the CVM instance to which it is mounted. In simple terms, the local disk starts and ends along with the startup and shutdown of the CVM it is mounted to.
Note
The local disk is the local storage from the physical machine where the mounted CVM instance is located. Currently, it can only be used as a data disk of the CVM. Some types of CVMs, such as high IO instances, need to be equipped with local SSD hard disks to obtain higher I/O read and write performance of the data disk.
Please note that local storage is not suitable for scenarios where there is no data redundancy architecture at the application layer and there is a risk of data loss (for example, when the host machine crashes). We strongly recommend that you use an instance that allows you to select a CBS as a data disk.