Dell PowerVault MD3220 - Manual (Page 179)

Configuration: Device Mapper Multipath for Linux 179
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Configuration: Device Mapper
Multipath for Linux
Overview
The MD3200 Series storage array uses a Linux operating system software
framework, known as Device Mapper (DM), to enable multipath capabilities
on Linux Host Servers. The DM multipath functionality is provided by a
combination of drivers and utilities. This chapter describes how to use those
utilities to complete the process of enabling MD3200 Series storage array on a
Linux system.
NOTE: The Device Mapper technology replaces an earlier, proprietary technology,
known as MPP. MPP was used to enable multipathing for the previous MD
generation MD3000 Series storage arrays.
NOTE: The required Device Mapper software components are installed on a Linux
host server by running the MD3200 Series Resource media installation program on
the server, and selecting either the Full or Host install option. For detailed
installation procedures, see the Dell PowerVault MD3200 and MD3220 storage
arrays Deployment Guide at dell.com/support/manuals.
Benefits of using DM Multipath include:
• Detects path failure and re-routes I/O to other available paths
• Revalidates failed paths after path restoration
• Utilizes multiple available paths to maximize performance
• Reconfigures path usage based on path states and error conditions
• Unifies multiple device nodes into a single logical multipath device node
• Indentifies a new multipathed LU and automatically configures a new
multipath node
• Provides device name persistency for DM devices under /dev/mapper/
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