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  • 1.  Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/17/24 11:29 AM
    Edited by Peter Wyder 01/17/24 11:30 AM

    Hi everyone

    I am faced with a puzzle:

    We have a hyperswap cluster (2xFS9500) that serves disks to our many hosts.

    I also have a couple SVC nodes (4xSV2) that I am triying to use as a "sandbox" system. Right now they are configured as a streched cluster, but without any disks attached to them. I then zoned the SVC nodes to our 2 FS9500 enclosures and configured them as hosts/hostcluster. I created 2 sets of single sites volumes and provisioned them to the SVC nodes.

    But when I refreshed the mdisks on the SVC cluster no additional (there is a quorum disk already) external mdisks were found. I then had a look at the fibrechannel connectivity on the SVC nodes and I saw that the FS9500 were visible (and the SVC nodes were also logged in on the hyperswap cluster).

    But instead of showing the FS9500 WWNs as "storage system" (like the quorum disk system) it showed tham as "node" (as if I could link them together).

    What am I doing wrong, did I misconfigure something?

    Thanks and cheers

    Peter



    ------------------------------
    Peter Wyder
    Senior DevOps Engineer Storage
    Zürcher Kantonalbank
    ------------------------------



  • 2.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 02:32 AM

    Hello Peter,

    Are you sure that an FS9x00 cluster with 2 IOgroups behind an SVC is supported?
    Disks from the FS9x00 backend come from 2 IOgroups and are offered to an SVC Cluster with 2 IOgroups.
    In the past we first had to unbundle an FS7x00 cluster after which we could map it to an SVC cluster again.

    Statement in Redbook Performance and Best Practices Guide for IBM Storage FlashSystem and IBM SAN Volume Controller:

    It is recommended that you add each controller enclosure (I/O group) of an IBM FlashSystem back-end as its own controller, that is, do not
    cluster IBM FlashSystem when it acts as an external storage controller behind another IBM Storage Virtualize product, such as SVC.

    But maybe IBM support can clarify this.

    Greets.



    ------------------------------
    TMasteen
    ------------------------------



  • 3.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 11:54 AM

    Hi T

    To be honest I dodn't know where to look if that was even supported. My thoughts were that the SVC nodes should basically work as Linux client hosts regarding the hyperswap cluster. Reading the excerpt you cited it seems to "only" be a recommendation to not cluster the flashsystems and not a "it just doesn't work" statement. But maybe I'm wrong here.

    Cheers

    Peter



    ------------------------------
    Peter Wyder
    Senior DevOps Engineer Storage
    Zürcher Kantonalbank
    Zürich
    ------------------------------

    Original Message


  • 4.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 01:10 PM

    Peter, 

    Having a FlashSystem behind a SVC cluster is not strange or not supported. The "problem" is having Vdisks\MDisks from multiple (clustered) IOgroups from the backend.
    One of the statements of IBM support that time was: Volumes presented to SVC nodes or other Spectrum Virtualize systems(Storwize, Flash) can only be accessible through a single I/O group

    But then again, maybe IBM support can tell us.

    Greets,



    ------------------------------
    TMasteen
    ------------------------------

    Original Message


  • 5.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 03:09 AM

    Hi Peter,

    Which npiv wwpn's used in your svc-to-9500 zones? As you already know there is 3 wwpn's on each port of 9500. One is for storage-to-storage connectivity, one is for scsi hosts and the last one is for nvme hosts. You can check this via lstargetportfc command on 9500 and check your zone uses the right npiv wwpn for svc connectivity. 



    ------------------------------
    Nezih Boyacioglu
    ------------------------------



  • 6.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 11:47 AM

    Hi Nezih

    I created peer zones (Brocade SAN) containing NPIV SCSI WWNs of the FS9500 ports and physical/hardware WWNs of all SVC nodes.

    According to my thinking this should be OK since the SVC nodes are "client hosts" connecting to the FS9500 enclosures. And btw. I had it differently before - zoning physical WWNs to physical WWNs - and that didn't work at all.

    Cheers

    Peter



    ------------------------------
    Peter Wyder
    Senior DevOps Engineer Storage
    Zürcher Kantonalbank
    Zürich
    ------------------------------

    Original Message


  • 7.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 03:21 AM

    Hi Peter,

     

    You may check the "system layer" option which should be set to "storage" on FlashSystem so it can be seen as a virtualizable backend disk system by SVC (and not a potential replication or cluster partner). On SVC side, it should be set to "replication".

    The command to run on FlashSystem is "chsystem -layer storage".

     

     

    You might not be able to change it if you are in a HyperSwap topology, though. Maybe someone can confirm if this is a problem.

     

    Erwan AUFFRET

    Storage Specialist

    IBM Technology, France

    Email : erwan.auffret@fr.ibm.com

    06.26.55.29.05

     

         

     

    Unless otherwise stated above:

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  • 8.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/18/24 11:51 AM

    Hi Erwann

    Both clusters (the FS9500 hyperswap cluster and the SVC streched cluster) are in "replication" layer mode. At least from the FS9500 hyperswap cluster I know this has to be that way otherwise I couldn't connect the FC quorum disk (having the cluster in "storage" layer mode doesn't allow fro external storage to be connected - what the quorum disk is.

    So it seems I can't change neither of them.

    Cheers

    Peter



    ------------------------------
    Peter Wyder
    Senior DevOps Engineer Storage
    Zürcher Kantonalbank
    Zürich
    ------------------------------

    Original Message


  • 9.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/19/24 02:25 AM

    Hi,

    1. FlashSystem hyperswap volumes can not be mapped to svc, multiple io group and so in, as many others have said
    2. svc must be mapped to the scsi WWPNs in fs9500, otherwise it won't work. For fs9500 the svc is just another Linux host 


    ------------------------------
    ROGER ERIKSSON
    ------------------------------



  • 10.  RE: Hyperswap Cluster System as backend storage for SVC cluster?

    Posted 01/23/24 04:41 AM

    Hi Roger

    1. I mapped "single site" volumes (only accessible to the io group on that site) to the SVC nodes - still not showing up as external storage
    2. That's exactly what I did :)

    Cheers

    Peter



    ------------------------------
    Peter Wyder
    Senior DevOps Engineer Storage
    Zürcher Kantonalbank
    Zürich
    ------------------------------

    Original Message


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