3 Replies Latest reply on Mar 6, 2013 10:16 AM by 992759

    2540 - Multipathing and LVM raid issue

      I have two servers (X3-2 with RH6.3) connected on two 2540 with fiber. Multipath configuration is by default.
      Each 2540 map one identical volume. On my server, with these two volumes, I build a LVM raid 1.
      I have two controllers by storage and two fibers by controllers.
      Multipath works well if I lose 1,2 or 3 fibers, or if I lose one controller.
      But if I lose one 2540 completely (electrically or 2 controllers) I lose my datastore.
      I lose the connection on the second 2540. I have no more access to my raid 1.
      The goal is to keep the access to the storage if I lose one 2540.
      I don't understand if my problem come from multipath configuration or from the LVM configuration.

      Any help is welcome.
        • 1. Re: 2540 - Multipathing and LVM raid issue
          Multipath can cover problem with access path to array. According you message it's work fine.

          LVM should cover problem when you whole lost one storage. According with your message it's not work.

          So you should check your LVM configuration and analise logs and messages when you lost one storage.

          • 2. Re: 2540 - Multipathing and LVM raid issue
            Ok, so I think I lose the access to the raid because it was created by default : lvcreate -L 55G -m1 -n lv0 vg0
            In this case, implicitly it is a mirror. As I have only two disks, the logs are on the raid. So If I lose a disk, my logical volume will be unusable.
            lvm.conf :
            mirror_log_fault_policy = "allocate"
            mirror_image_fault_policy = "remove"

            So I tried to rebuild my LV but this time specifying as option "raid1"
            # lvcreate --type raid1 -L 55G -m1 -n lv0 vg0

            But I have an error when I specify "raid1"
            # device-mapper: reload ioctl on failed: Invalid argument
            # Failed to activate new LV.
            • 3. Re: 2540 - Multipathing and LVM raid issue
              I just test the same command but this time on a EL6 (2.6.32-279.el6.x86_64)
              and the command "# lvcreate --type raid1 -m 1 -L 2G -n lv0 vg0" works fine.

              So, is that the raid1 LVM type is compatible with Oracle Linux 6 Unbreakable?