Users Guide

Table Of Contents
Using the Multipath I/O Component
The Dell EqualLogic Multipath I/O (MPIO) DSM (Device Specific Module) enables you to configure redundant network paths
from a Windows computer to PS Series volumes for high availability and high-performance SAN data traffic.
Topics:
Introduction to Multipath I/O DSM
Prerequisites for Configuring Multipath I/O DSM
Requirements for Multipath I/O
Configure Multipath I/O Between a Computer and a Group
View MPIO Sessions
Set the MPIO Load-Balancing Policy
EqualLogic MPIO Configuration Tool
Introduction to Multipath I/O DSM
The Dell EqualLogic MPIO DSM coordinates activity between the MPIO drivers and PS Series group storage, maximizing the
capabilities of both the operating system and the iSCSI SAN.
The MPIO component works with the iSCSI initiator and MPIO driver to improve both reliability and performance. The
component consists of a kernel driver (eqldsm.sys) and a user mode service (EHCMservice.exe).
If the Host Integration Kit installation included the option to import EqualLogic volumes to a PowerStore array, the MPIO
component consists of a kernel driver (dcdsm.sys) and user mode services (EHCMservice.exe and DC-
HAService.exe)."
When you install the MPIO DSM on a Windows operating system, it establishes and manages multiple I/O data paths to the
same iSCSI target (a PS Series volume). If a fatal path failure occurs, the failure is quickly detected and I/O transparently fails
over to a functioning path. The MPIO DSM recognizes and responds to a variety of network errors, device errors, and timeout
conditions.
The MPIO DSM provides the following features:
Automatic connection management
Increased bandwidth
Reduced network latency
Automatic path failure detection and failover to a functioning path
Automatic load balancing across paths
Support for multiple connections to a single iSCSI target (volume)
Support for a variety of iSCSI initiators
Per-pool connection throttling
The following figure shows a typical multipath I/O configuration.
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Using the Multipath I/O Component 37