Primary Storage

  • 1.  Flashsystem host unmap not working ¿?

    Posted Fri October 22, 2021 03:30 PM
    Hi
    can somebody help me to understand the UNMAP function on the flashsystem.
    Or what i am doing wrong.
    I want to use UNMAP for my hosts ( generic hosts Windows & AIX), i got spectrum virtualize 8.4.0.5. Flashsystem 7200 with all flash FCM2 modules.
    I understand that UNMAP must be enable by default.
     lssystem command shows that host_unmap is not enable
    > lssystem
    ...
    host_unmap off
    ...
    So i enabled it:
    > chsystem -hostunmap on 
    now lssystem shows it enabled.

    For testing i type in a windows 2019 host:
    PS:> defrag D: /L
    but i got an error
    "the operation requested is not supported by the hardware backing the volume"
    same error with command.  PS:> Optimize-volume

    what am i doing wrong?

    thank you in advance for any help

    ------------------------------
    Arturo Garfias
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  • 2.  RE: Flashsystem host unmap not working ¿?

    Posted Mon October 25, 2021 10:43 AM
    Hi Arturo.

    I hope this article could help to clarify the usage for UNMAP SCSI for Spectrum Virtualize.

    https://www.ibm.com/support/pages/scsi-unmap-support-spectrum-virtualize-systems

    Kind regards.

    Luis Fer Becerra.

    ------------------------------
    Luis Fernando Becerra Lebaza
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  • 3.  RE: Flashsystem host unmap not working ¿?

    Posted Mon October 25, 2021 06:01 PM
    Hello Arturo

    AFAIK the command would be: svctask chsystem -unmap on  (The hostunmap is not a valid syntax)


    Then, remember that SCI unmap applies to format, create operations. I don´t sure about defrag. But i hope the above lines can help you.

    Regards

    ------------------------------
    Humberto Sosa
    ------------------------------



  • 4.  RE: Flashsystem host unmap not working ¿?

    Posted Tue October 26, 2021 03:54 AM

    Hi,
    on newer firmwares there are two commands

    SCSI Unmap can be disabled using the CLI command:
    svctask chsystem -backendunmap off
    svctask chsystem -hostunmap off

    To re-enable SCSI Unmap, use the
    svctask chsystem -backendunmap on
    svctask chsystem -hostunmap on

    On Standard pools you will only see that the used capacity of the FCM goes down, not the size of the thin provisioned volumes.

    https://docs.microsoft.com/en-us/windows-hardware/drivers/storage/thin-provisioning

    https://www.vembu.com/blog/reclaiming-space-using-trim-unmap/ 



    ------------------------------
    Bernd Albrecht
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