IBM AIX-AK FZK 2005 manual Multipathing Concepts

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IBM Systems Group

Multipathing Concepts

Linux host 1	Linux host 2
HBA 0 HBA 1	HBA 0 HBA 1

	Linux host 1				Linux host 2
	HBA 0 HBA 1			HBA 0 HBA 1			2
					1	DS8000	2
						DS8000
Linux host 1	Linux host 2					Disk
HBA 0 HBA 1	HBA 0 HBA 1					Disk
	1				2	LUN 0
	1	DS6000			2
		DS6000
A DS4000 B			Disk
A DS4000 B			LUN 0

Disk

LUN 0

AIX-AK FZK 2005

© 2005 IBM Corporation

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Contents AIX AK April 2005 Forschungszentrum Karlsruhe IBM Storage with Linux Topics  What is supported What Is SupportedIBM Storage Support for Linux  DS4000 SLES8, SLES9, RH-EL PLinux Support Disk DS6000, DS8000 SLES8, SLES9, RH-EL  LTO Sles 8, Sles 9, RH-EL PLinux Support Tape 359x Sles 8, Sles 9, RH-EL  Parallel Scsi attachment also supported  AdvancedLinux Scsi Subsystem Everything is a file Linux Device AddressingUpper level DesignLinux Kernel Version Storage Changes in Linux Kernel Still there Wellknown Linux Scsi Limitations ESS, DS6000, DS8000 Specific Other Problems and Pitfalls Multiple LUN support of RH-EL  DS4000 Specific  Linux Kernel Limits Large filesystems supportMultipathing Scenarios Multipathing Concepts  DS4000 transfers LUNs to alternate controller  Two multipathing solutions availableLUN Transfer to Alternate Controller LUN Thrashing Scenario LUN Thrashing Scenario LUN Thrashing Scenario Multipathing with Rdac  Must run mppUpdate after each configuration changeRdac Shared Data Scenario Rdac Shared Data Scenario Rdac Shared Data Scenario  SDD knows preferred path automatically Preferred Path DS6000 uses concept of preferred path Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario  ESS and DS8000 have independent host ports Host Ports Independent of ControllerIndependent Host Port Shared Data Scenario Independent Host Port Shared Data Scenario Independent Host Port Shared Data Scenario Tape Specifics  Daemon IBMtaped IBMtape driver For download as source code  Build and install using make  ProvidesIBMtapeUtil  3rd party applications Use LTO Devices Native Native Library Management Medium Changer Failover One driver for all HBAs Tape and Disk Connected to the Same HBAQuestions & Discussion ESS / DS6000 / DS8000 Resources DS4000 Resources LTO Resources Redbooks White Papers Legal Notices