LINUX下多路径multi-path的原理及使用方法是什么

Linux下多路径multi-path的原理及使用方法是什么

Multi-path I/O in Linux allows a single I/O request to be split into multiple I/O requests and sent over different physical paths to the same storage device. This can provide increased performance and/or redundancy in the event of a path failure.

Multi-path I/O can be implemented in one of two ways:

1. Using a hardware solution that supports multiple I/O paths to a storage device

2. Using a software solution that creates multiple I/O paths to a storage device

In either case, the Linux kernel will present a single logical device to the user that is composed of multiple physical devices.

Multi-path I/O is most commonly used in storage area networks (SANs) where multiple I/O paths are available to storage devices. However, it can also be used in direct-attached storage (DAS) systems where multiple storage devices are connected to a single server.

Multi-path I/O can be used with any type of storage device that can be accessed over multiple I/O paths, including hard disk drives, solid state drives, and storage arrays.

When configuring multi-path I/O, it is important to consider the following:

1. The number of I/O paths that will be used

2. The type of multipathing software that will be used

3. The configuration of the storage devices

4. The performance and redundancy requirements

The number of I/O paths that will be used will depend on the type of storage device and the number of physical paths that are available. For example, a hard disk drive connected to a server via two SAS ports will have four I/O paths (two paths per port).

The type of multipathing software that will be used will also depend on the type of storage device. For hard disk drives, the most common type of multipathing software is the Linux Logical Volume Manager (LVM). For storage arrays, the most common type of multipathing software is the storage array's proprietary multipathing software.

The configuration of the storage devices will also need to be considered. For example, if using LVM, the storage devices will need to be configured as LVM physical volumes.

The performance and redundancy requirements will also need to be considered when configuring multi-path I/O. For example, if increased performance is required, more I/O paths may be used. If increased redundancy is required, more I/O paths may be used and/or redundant storage devices may be used.