PowerHA now supports logical unit (LUN) level switching on the SAN Volume Controller (SVC), Storwize V7000, and Storwize V3700. This support is similar to the LUN level switching available for System Storage DS8000 allowing users to switch an independent auxiliary storage pool (IASP) at a LUN level between logical partitions in a PowerHA cluster. This is not a disaster recovery mechanism but a high availability mechanism as a single copy of the IASP is switched between LPARs by altering the host connections on the storage subsystem. This technology can be used together with copy services (FlashCopy, Metro Mirror, and Global Mirror) on the SVC and Storwize V7000 as well as IBM i Geographic Mirroring.
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PowerHA LUN-Level switching is not compatible with SVC or IBM FlashSystems Volume protection. Volume protection must be disabled for the entire storage device to use LUN-Level switching. If volume protection is enabled, PowerHA will issue an HAE0096 indicating that volume protection must be disabled. Volume protection can be disabled with either the command line or GUI interface. See https://www.ibm.com/docs/en/flashsystem-7x00/8.3.x?topic=volumes-changing-volume-protection-settings in the SVC documentation for additional information. An IBM idea exists to enhance PowerHA to check for volume protection on a pool or child-pool level, rather than at the storage device level. This enhancement would allow for volume protection to be on for all disk units except for those in the pool that the IASP disk units are in. If this enhancement is of interest see https://ibm-power-systems.ideas.ibm.com/ideas/IBMI-I-2628 to provide your vote comments. |