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SGC_Pool: Total percent used difference

  • 1.  SGC_Pool: Total percent used difference

    Posted 05/12/26 12:22 PM

    IBM Safeguarded Copy for IBM i

    WRKSGCPY ENV(GDIHQ1SGC)

    F14=Display Volume capacities

    If I pick anyone of the three environments the Total percent used is within .02 percent.

    On the FS7300 GUI I'm seeing a different number:



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    Robert Berendt IBMChampion
    Business Systems Analyst, Lead
    Dekko
    Fort Wayne
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  • 2.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 12:55 PM
    Edited by Robert Berendt 05/12/26 12:58 PM

    IBM_FlashSystem:FS7300USSI:rob>lsmdiskgrp -delim :
    id:name:status:mdisk_count:vdisk_count:capacity:extent_size:free_capacity:virtual_capacity:used_capacity:real_capacity:overallocation:warning:easy_tier:easy_tier_status:compression_active:compression_virtual_capacity:compression_compressed_capacity:compression_uncompressed_capacity:parent_mdisk_grp_id:parent_mdisk_grp_name:child_mdisk_grp_count:child_mdisk_grp_capacity:type:encrypt:owner_type:owner_id:owner_name:site_id:site_name:data_reduction:used_capacity_before_reduction: used_capacity_after_reduction:overhead_capacity:deduplication_capacity_saving:reclaimable_capacity:easy_tier_fcm_over_allocation_max:provisioning_policy_id:provisioning_policy_name:replication_pool_link_uid
    0:INDY_Pool:online:1:281:325.40TB:2048:261.40TB:41.01TB:41.01TB:41.01TB:12:80:auto:balanced:no:0.00MB:0.00MB:0.00MB:0:INDY_Pool:1:23.00TB:parent:yes:none:::::no:0.00MB:0.00MB:0.00MB:0.00MB:0.00MB:101%:::0000000000008EB80000020420415230
    1:SGC_Pool:online:0:1442:23.00TB:2048:3.07TB:211.23TB:14.20TB:19.16TB:918:85:auto:balanced:no:0.00MB:0.00MB:0.00MB:0:INDY_Pool:0:0.00MB:child_thick:yes:safeguarded_copy:::::no:0.00MB:0.00MB:0.00MB:0.00MB:0.00MB:100%:::0000000000008EB90000020420415230



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    Robert Berendt IBMChampion
    Business Systems Analyst, Lead
    Dekko
    Fort Wayne
    ------------------------------



  • 3.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 03:41 PM
    Edited by Nezih Boyacioglu 05/12/26 03:41 PM

    Hi Robert,

    One possibility is that space is not being reclaimed on the FlashSystem side after safeguarded copies are deleted. Could you check whether host unmap is enabled on the FlashSystem 7300 (lssystem | grep unmap).  If it is disabled (off), you can enable it with: chsystem -hostunmap on 

    FlashSystem supports "scsi unmap" space reclamation from supported hosts. If unmap is not active, deleted blocks may not be reclaimed immediately, which could explain why the child pool is showing a much higher utilization on the FlashSystem side than on IBM i.



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    Nezih Boyacioglu
    IBM Community Hero
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    Original Message


  • 4.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 03:45 PM

    IBM_FlashSystem:FS7300USSI:rob>lssystem | grep unmap
    host_unmap off
    backend_unmap on



    ------------------------------
    Robert Berendt IBMChampion
    Business Systems Analyst, Lead
    Dekko
    Fort Wayne
    ------------------------------

    Original Message


  • 5.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 03:50 PM

    IBM_FlashSystem:FS7300USSI:rob>chsystem -hostunmap on
    IBM_FlashSystem:FS7300USSI:rob>lssystem | grep unmap
    host_unmap on
    backend_unmap on

    When does it reclaim the space?  Some nightly batch process?  Or it started with the change but it just takes a long background time?



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    Robert Berendt IBMChampion
    Business Systems Analyst, Lead
    Dekko
    Fort Wayne
    ------------------------------

    Original Message


  • 6.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 03:56 PM
    Edited by Nezih Boyacioglu 05/12/26 03:56 PM

    I'm not familiar with IBM i, if it supports scsi unmap it will starts soon. If you have IBM Storage Insights you can also check and see unmap process on performance screen of your FS7300 (choose Metrics > volume data rate > unmap)



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    Nezih Boyacioglu
    IBM Community Hero
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    Original Message


  • 7.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 04:09 PM

    I wonder if I don't have the storage insights.  I don't see "volume data rate".



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    Robert Berendt IBMChampion
    Business Systems Analyst, Lead
    Dekko
    Fort Wayne
    ------------------------------

    Original Message


  • 8.  RE: SGC_Pool: Total percent used difference

    Posted 05/12/26 04:24 PM

    Hi Nezih,

    IBM i does support unmap.

    https://www.ibm.com/support/pages/what-smfsunmapworker-task



    ------------------------------
    Uwe Schreiber
    System Engineer / Solution Architect
    SVA System Vertrieb Alexander GmbH
    Wiesbaden
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    Original Message


  • 9.  RE: SGC_Pool: Total percent used difference

    Posted 05/13/26 09:57 AM

    Thank you Uwe, really appreciate people in the community taking the time to help others.
    A simple hello or thank you goes a long way and makes communities much better places for everyone.



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    Nezih Boyacioglu
    IBM Community Hero
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    Original Message


  • 10.  RE: SGC_Pool: Total percent used difference

    Posted 05/13/26 12:33 PM

    If you want a definitive answer you'll need to open a ticket.  Looking at the numbers in the lsmdiskgrp and what you have on the GUI, I don't see a match between the 87% (19.93Tib) shown by the GUI and any of the numbers in the cli output.  The closest is real_capacity at 19.16 TiB.  Note that while the CLI shows a TB suffix, that is actually tebibytes (TiB) as documented here:  https://www.ibm.com/docs/en/flashsystem-9x00/8.7.0?topic=reference-understanding-capacity-indicators

    The toolkit uses the lsmdiskgrp to calculate the result (converting to Terabytes, which is a better fit to  all other IBM i capacity reporting)  The calculation of the percentage used is used_capacity/capacity.

    I suspect from that output that you are using CSM managed safeguarded copy based on legacy flashcopy.  Flashsystem and the SGC toolkit now support internally managed volume group snapshots for safeguarded copy, which can eliminate the need for the child pool and CSM in your environment.  



    ------------------------------
    Vincent Greene
    IT Consultant
    Technology Expert labs
    IBM
    Vincent.Greene@ibm.com


    The postings on this site are my own and don't necessarily represent IBM's positions, strategies or opinions.
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    Original Message


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