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Storage CH is a source for all Storage related topics. The postings on this site are my own and don’t necessarily represent IBM’s positions, strategies or opinions.

Roger Luethy, Storage Specialist at IBM Switzerland, 27 years of Storage/Networking/IT experience and loves Sport,Travel,Photography,Blogging

Roger Luethy

P.S. : If you are into Photography please visit my Deviantart Page or my Tumblr Page

21 Comments
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21 Comments

  1. Guillaume

     /  July 12, 2012

    Hi Roger
    Thanks for your blog I found interesting informations.
    We have just migrated our storage from EMC to IBM (SVC + DS3500)
    I have a question regarding multipath with IBM. I can’t find any GUI as we had with EMC powerpath monitor to see real time the state of the paths

    For SVC it seems SDDSM has some command line “datapath query device” but no real time and for DS3500 I didn’t find any tool even command line to see the paths. (The same Windows server has Lun on SVC and DS3500)

    Do you know if there is a way to see the paths on DS3500 or even better a tool like we had with EMC powerpath monitor ?

    thanks

    Reply

  2. rogerluethy

     /  July 13, 2012

    Hi Guillaume

    Thank you :-) Yes with SDDSM you can check on the paths (did you have a look at this document ->http://www-01.ibm.com/support/docview.wss?uid=ssg1S7000303&aid=11 Chapter 3 ?). For the DS3500 you may check ->http://download.boulder.ibm.com/ibmdl/pub/systems/support/system_x_pdf/00w0186.pdf
    but i’m not aware of a status Monitor for the paths in the DS3500.

    -Roger

    Reply

  3. Guillaume

     /  July 16, 2012

    Hi Roger

    sorry to pollute your blog, but it didn’t find any other way to write you – You can delete these posts

    in fact I found what I was looking for. I’m now using the HP MPIO manager (it is a snap-in in Storage / Device Manager) where you can see all your paths state in the GUI. It works better for DS3500 than SVC

    It’s a pain, that we must use HP tool to get something. As you’re working at IBM if you know someone there, you can tell them that HP or even EMC(powerpath monitor) have nice tools IBM customer need.

    thanks,
    Guillaume

    Reply

  4. Brian Beeler

     /  March 5, 2013

    Roger – it’s come to our attention today via Seagate’s blog that you used our hybrid image that we created in one of your posts without giving attribution. It appears you deep linked too, so we can take it down, but I’d rather just a tip of the hat with a link to our site :)

    http://rogerluethy.wordpress.com/2012/09/11/designing-hybrid-storage-for-the-enterprise/

    Reply

  5. Shortie

     /  April 15, 2013

    Hi, I was wondering if anyone else has encountered an issue with the loss of available partitions on an IBM 1818 DS5100 / DS5300 & DCS3700 when updating to CFW version 07.84 ?
    I am aware of at least 2 situations where that appears to have happened but have so far been unable to find any threads out there.
    There’s a ironic twist if this is the case because one of the benefits that V07.84 is designed to give is additional “base” partitions.
    Very best regards
    Shortie

    Reply

  6. John

     /  April 26, 2013

    Hi Roger,

    I have a query regarding IBM SVC Global mirror . We have a global mirror configured between two sites, We are planning to shutdown the host connected to primary and breaks the global mirror after some time .Is it possible to get the exact same copy of data primary in secondary site . Is there any specific cooling peroid for copying data from primary to secondary site, can I verify this process.

    Reply

    • rogerluethy

       /  April 26, 2013

      Hi John

      If I/O operations on the primary volume are paused for a small length of time, the secondary volume can become an exact match of the primary volume. You can find more details in the SVC Information Center ->http://pic.dhe.ibm.com/infocenter/svc/ic/index.jsp or in the Redbook ->http://publib-b.boulder.ibm.com/abstracts/sg247574.html Chapter 3 also 3.10

      Hope this helps

      -Roger

      Reply

      • John

         /  April 26, 2013

        Thanks Roger for the quick reply. Does a consistent sychronised mirror means the primary and secondary are the same or is there any way I can verify this. In metro and global mirror relationship tab there is a row which shows the percentage of data transfer for each volume . But I never saw it in 100% even though the volume is in consistent synch state. May be this is because there might be write i/o happening in primary. If we stops the i/o to the primary volume will the data transfer rate in the metro and global mirror relationship tab will become 100% .

      • rogerluethy

         /  April 26, 2013

        John,
        It’s because there are Write IOs to the Primary else (stopped IO on Primary) it should show 100%. A synchronous Mirror (Metro Mirror) has always the same (consistent) data on both side. On a asynchronous Mirror (Global Mirror) the Secondary side is lagging behind the Primary.

        -Roger

  7. John

     /  April 26, 2013

    Thanks Roger , as we are stopping the I/O on primary volume the secondary should be in sync soon. However is there a way I can determine whether the primary and secondary volumes are consistant over a period of time after the I/O stops on primary.

    Reply

  8. John

     /  April 26, 2013

    Sorry to bother once again , I am not getting any value for progress in lsrcrelationship, does that means it is in sync. I am attching the output .
    name ecrp1dbp_sd19
    master_cluster_id 0000020060414862
    master_cluster_name UK-HFD-SVC1
    master_vdisk_id 95
    master_vdisk_name ecrp1dbp_sd19
    aux_cluster_id 0000020060214A68
    aux_cluster_name SP-HFD-SVC1
    aux_vdisk_id 312
    aux_vdisk_name ecrp1dbp_sd19
    primary master
    consistency_group_id 3
    consistency_group_name ecrp1dbp_R
    state consistent_synchronized
    bg_copy_priority 50
    progress
    freeze_time
    status online
    sync
    copy_type global

    Reply

  9. John

     /  April 26, 2013

    Thanks Roger . One last thing regarding replication , while we are doing the activity we will stop the mirror and some activity will be performed at Site A (primary) . Due to some reason we dont require the changes which is happened at Site A (primary) Then we will reverse the replication, ie Site A will become secondary and Site B will become primary. My question is when we change the replication direction only the changes which is happened at Site A will be removed or else it will copy the entire data in Site B to Site A ie a full refresh.

    Reply

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