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  • 1.  Moving Vdisks (with a FlashCopy mapping) to another IO-Group

    Posted Thu October 03, 2024 05:18 AM
    We currently have an SVC cluster with 3 IO groups. We want to reduce this to 2 IO groups.
    After some zoning changes from Hosts to the other IO groups, we can get started with:
    - addvdiskaccess
    - movevdisk
    - rmvdiskaccess
     
    My question concerns FlashCopy mappings. The FC-Source and FC-Target VDisks have the same caching IO-Group.
    The documentation states: You can move a volume that is in a FlashCopy mapping, but the FlashCopy bitmaps remain in the original I/O group.
    Does this applies to both the FC_Source and the FC_Target? So can I move both to another I/O Group?
     
    I have the option to wait before deleting IO-Group 3 until those mappings are gone.
    Thanks.


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    TMasteen
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  • 2.  RE: Moving Vdisks (with a FlashCopy mapping) to another IO-Group

    Posted Fri October 04, 2024 04:07 AM
    Edited by Chris Canto Fri October 04, 2024 04:07 AM

    That's right, yes.  You can move the source and/or target of a FlashCopy map; the volume will move but the bitmap for the FlashCopy operation will still be held in the original I/O group.  Once you've removed the map(s) then the dependency on the original I/O group will be removed.

    Using the CLI, you can use the "lsiogrp <id/name>" view to look at the amount of memory being used for FlashCopy in an I/O group, so you'll be able to check that has gone to zero when you think you've finished the migration+deletion work, before removing the nodes in the I/O group.



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    Chris Canto
    Software Developer
    IBM
    Hursley
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  • 3.  RE: Moving Vdisks (with a FlashCopy mapping) to another IO-Group

    Posted Fri October 04, 2024 09:27 AM

    The difficult part to overcome is "Once you've removed the map(s) then the dependency on the original I/O group will be removed."

    Unfortunately, the only way to remove the FC Map is to delete all the FC Mappings for source and target volumes.  Meaning any sync'd FC's you have will need to be re-mapped and re-sync'd.



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    Randy Frye
    Senior Storage Administrator
    D&H Distributing
    Harrisburg
    7173647948
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