Technical data

1IntroductiontoHPDMMultipath
This chapter addresses the following topics:
•Overview
•Features
•What'sNew
• Software Components
• HPDM Multipath Operation
Overview
HPDM Multipath software kit is an HP released Device Mapper multipath binary, based on Device
Mapper Multi
path included in Linux Operating System distributions, with enablement for HP
Storag eWor
ks Disk Arrays. Device Mapper is a n infrastructure in the Linux kernel. It provides a generic
way to creat
e virtual layers of block devices. It supports striping, mirroring, snapshots, concatenation,
and multip
athing. The multipath feature is provided with combination of DM Multipath kernel modules
and multipath-tools user-space package.
Features
nl
HPDM Mu ltipa th supports the following features:
• Detects path failure and automatically reroutes (failover) I/O to an available alternate path, if an
existing connection fails.
• Provides an option to perform failback of the LUN to the repaired paths.
• Implements failover or failback actions transparently without disrupting applications.
• Monitors each path and notifies if the path status changes.
• Facilitates I/O load balancing among the multiple paths.
• Provides CLI with display options to configure and manage Multipath features.
• Provides an option to customize names for the HPDM Multipath devices.
• Provides device name persistence across reboots or confi guration SAN changes.
• Provides policy-based path grouping for the user to customize the I/O flow through specificsetof
paths.
• Provides online LU N addition and deletion support.
• Provides suppor t for the HP StorageWorks Arrays (EVA-AA, MSA-AA, and XP) with latest firmware
revisions.
• Provides multipathing in clustere d environment.
• Provides support for multipathing devices to be c on figured under Logical Volume Manager.
What’s New
HPDM M
ultipath provides the following additional features as par t of this version:
• Provides support for RHEL4.5/RHEL4.6/RHEL5.1/SLES9 SP4 and SLES10 SP1 along with
RHEL5/SLES9 SP3/SLES10 OS distributions.
• Provid es support for HP StorageWorks EVA4400 Disk Arrays.
• Prov
ides support for HP StorageWorks MSA1000/1500 Disk Arrays.
• Provides support for HP StorageWorks MSA2000 Product family Disk Arrays
(MSA2012fc/MSA2212fc/MSA2012i).
Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays
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