Topic
5 replies Latest Post - ‏2013-02-27T22:36:57Z by PPriit
SystemAdmin
SystemAdmin
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Pinned topic Assigning LUNS to multiple wwns.

‏2013-02-25T07:33:24Z |
Hi,

we have IBM storage 3500 and need to share the lun's to servers.

Host group 1: LUN1:to be mapped to server1, server2
Host group 2: LUN2:to be mapped to server2, server3
Host group 3: LUN3:to be mapped to server4

But when I try to map LUN 2 to server 2 , it tells that the port identifier is already in use(in LUN1) and cannot use.

I am not able to map more than one LUN using a single WWN outside a host group.

Please advice.

Regards,
ITlearner
Updated on 2013-02-27T22:36:57Z at 2013-02-27T22:36:57Z by PPriit
  • Berniebgbb
    Berniebgbb
    83 Posts
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    Re: Assigning LUNS to multiple wwns.

    ‏2013-02-25T10:29:09Z  in response to SystemAdmin
    Sounds like you have associated the same "unique identifier/s" to multiple hosts to enable you to create your multiple host groups with the same host......(can you confirm)

    For your configuration maybe the best bet is to not create host groups.
    Just define your four hosts with their relevant unique port identifiers and map the LUN's directly to each Host.(Multiple hosts where required...)

    Must say I have not tried this specific configuration, but can't see why you would not be able to do it this way...

    Worth a shot...I'll see if I can try it tomorrow @ work.

    Bernie.
    • SystemAdmin
      SystemAdmin
      4779 Posts
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      Re: Assigning LUNS to multiple wwns.

      ‏2013-02-25T12:39:37Z  in response to Berniebgbb
      NO luck. it throws the same error.
      Irrespective of having a host group or not, the error appears when a single WWN is repeated to allocate with another LUN or host.

      attached is the error snapshot.
      • Berniebgbb
        Berniebgbb
        83 Posts
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        Re: Assigning LUNS to multiple wwns.

        ‏2013-02-26T09:17:19Z  in response to SystemAdmin
        Still sounds (and looks from the screen shot) that you are trying to associate the same HBA WWN with two different hosts?? you don't do that.

        Each "registered host" has to have a unique HBA WWN assigned, you can not assign the same WWN multiple times.

        Can you explain the following

        1. How many physical hosts do you have?
        2. what names have you given them?
        3. how many HBA's in each physical host and what are their WWN's?
        4. what OS are they running?
        From what you have said it sounds like you have 4 hosts (physical separate servers), each one should have its own HBA WWN assigned

        Host 1. --> WWN: 00:00:00:00:00:00.....
        Host 2. --> WWN: 11:11:11:11:11:11.....
        Host 3. --> WWN: 22:22:22:22:22:22.....
        Host 4. ---> and so on....

        From there, grab each LUN and map it to the hosts you have created above, "multi-map" (map same LUN to Multiple hosts) as required.

        Does that make sense?

        Bernie.
        • SystemAdmin
          SystemAdmin
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          Re: Assigning LUNS to multiple wwns.

          ‏2013-02-27T06:44:11Z  in response to Berniebgbb
          Yes I have 3 physical servers. And I can map the LUNS to them. The problem is, I have a management server where I need to see all the LUN's that are assigned to these 3 servers.

          Eg: 3 LUN's , 3 physical servers.
          Mapping 1 LUN to 1 server.

          Now I want to see all these 3 LUN's in 4th server which has only 1 WWN.When I add the WWN of 4th server to first server, it accepts.But when I try to map the same wwn to 2nd,3rd servers it throws the attached error.

          So is there any possibility that this wwn can be mapped to all 3 LUN's .
          • PPriit
            PPriit
            2 Posts
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            Re: Assigning LUNS to multiple wwns.

            ‏2013-02-27T22:36:57Z  in response to SystemAdmin
            It's a little bit confusing, what you are writing in your last post, compared to your first post. But one scenario can be, there you create a host group and define all your hosts in that group, with all their WWN's. Now you map your LUN's to that host group. After that, you use software from your HBA vendor (Emulex One Command Manager or QLogic HBAAnythere) and mask unwanted LUN's inside operating system.

            Priit