IBM AIX-AK FZK 2005 LUN Transfer to Alternate Controller,  Two multipathing solutions available

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IBM Systems Group

LUN Transfer to Alternate Controller

DS4000 transfers LUNs to alternate controller

Volumes are owned by one controller

Volumes can be accessed through both controllers

Volume ownership is always transferred to the controller that is used for volume access -> transfer time approx 1 s

Two multipathing solutions available

QLogic failover driver uses AVT

Difficult to configure

Potential LUN thrashing

RDAC uses inband communication

Self configuring

Suitable for data sharing scenarios

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 PLinux Support Disk  DS6000, DS8000 SLES8, SLES9, RH-EL DS4000 SLES8, SLES9, RH-EL  359x Sles 8, Sles 9, RH-EL PLinux Support Tape LTO Sles 8, Sles 9, RH-EL  Parallel Scsi attachment also supported  AdvancedLinux Scsi Subsystem Linux Device Addressing Everything is a fileDesign Upper levelLinux Kernel Version Storage Changes in Linux Kernel Wellknown Linux Scsi Limitations Still thereOther Problems and Pitfalls  Multiple LUN support of RH-EL  DS4000 Specific ESS, DS6000, DS8000 Specific Large filesystems support  Linux Kernel LimitsMultipathing Scenarios Multipathing Concepts  Two multipathing solutions available LUN Transfer to Alternate Controller DS4000 transfers LUNs to alternate controller LUN Thrashing Scenario LUN Thrashing Scenario LUN Thrashing Scenario  Must run mppUpdate after each configuration change Multipathing with RdacRdac Shared Data Scenario Rdac Shared Data Scenario Rdac Shared Data Scenario Preferred Path  DS6000 uses concept of preferred path SDD knows preferred path automatically Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario Preferred Path Shared Data Scenario Host Ports Independent of Controller  ESS and DS8000 have independent host portsIndependent Host Port Shared Data Scenario Independent Host Port Shared Data Scenario Independent Host Port Shared Data Scenario Tape Specifics IBMtape driver  Daemon IBMtaped Build and install using make  Provides IBMtapeUtil For download as source code Use LTO Devices  Native 3rd party applications Native Library Management Medium Changer Failover Tape and Disk Connected to the Same HBA One driver for all HBAsQuestions & Discussion ESS / DS6000 / DS8000 Resources DS4000 Resources LTO Resources Redbooks White Papers Legal Notices