4 Replies Latest reply: Aug 6, 2012 10:25 AM by 898553 RSS

    Help with Multipath

    691078
      Hi All,

      When I execute multipath -ll command that time display only 3 path (orafra2,oradata2 and oradata1), not display other 2 path (orafra1 and data1). I have configure 5 path in /etc/multipath.conf file. What is the reason behind it. Please help me.

      Please find below some output for help:

      ###################################################

      [root@reuxeuls003 ~]# multipath -ll
      orafra2 (360060160a71e2100de29aae7f4f9de11) dm-10 DGC,RAID 10
      size=200G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
      |-+- policy='round-robin 0' prio=1 status=active
      | |- 1:0:1:3 sds 65:32 active ready running
      | `- 0:0:1:3 sdi 8:128 active ready running
      `-+- policy='round-robin 0' prio=0 status=enabled
      |- 1:0:0:3 sdn 8:208 active ready running
      `- 0:0:0:3 sdd 8:48 active ready running
      oradata2 (360060160951e2100ccc3b4800798df11) dm-9 DGC,RAID 10
      size=200G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
      |-+- policy='round-robin 0' prio=1 status=active
      | |- 1:0:0:4 sdo 8:224 active ready running
      | `- 0:0:0:4 sde 8:64 active ready running
      `-+- policy='round-robin 0' prio=0 status=enabled
      |- 1:0:1:4 sdt 65:48 active ready running
      `- 0:0:1:4 sdj 8:144 active ready running
      oradata1 (360060160a71e210002263e3fbde0dd11) dm-11 DGC,RAID 10
      size=300G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
      |-+- policy='round-robin 0' prio=1 status=active
      | |- 1:0:0:0 sdk 8:160 active ready running
      | `- 0:0:0:0 sda 8:0 active ready running
      `-+- policy='round-robin 0' prio=0 status=enabled
      |- 1:0:1:0 sdp 8:240 active ready running
      `- 0:0:1:0 sdf 8:80 active ready running

      ####################################################

      Output of multipath.conf file:

      ##################################################

      [root@reuxeuls003 ~]# egrep -v "^#|^$" /etc/multipath.conf
      defaults {
      user_friendly_names yes
      }
      multipaths {
      multipath {
      wwid 360060160a71e210002263e3fbde0dd11
      alias oradata1
      }
      multipath {
      wwid 360060160951e2100ccc3b4800798df11
      alias oradata2
      }
      multipath {
      wwid 360060160a71e21009a4a0a180fe7dd11
      alias orafra1
      }
      multipath {
      wwid 360060160a71e210080492a4f0fe7dd11
      alias data1
      }
      multipath {
      wwid 360060160a71e2100de29aae7f4f9de11
      alias orafra2
      }
      }
      [root@reuxeuls003 ~]#

      ####################################################

      Output of /var/log/messages :

      ####################################################


      [root@reuxeuls003 ~]# tail -10f /var/log/messages
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: long trespass command will be send
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: honor reservation bit will not be set (default)
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: long trespass command will be send
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: honor reservation bit will not be set (default)
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
      Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table

      ####################################################################

      Please help me.
      Thanks in advance.
        • 1. Re: Help with Multipath
          Billy~Verreynne
          Have you modified +/etc/udev/rules.d/40-multipath.rules+ ?

          What does the kernel say when discovering these EMC LUNs (prior to multipath loading)?

          What I/O fabric layer are you using? Fibre? Ethernet? SRP? And it would seem that EMC is being used (from the hwhandler output) - is Powerpath loaded and in use?

          Multipath does not do the device discovery and enumeration. That is done prior when the kernel boots and the I/O fabric layer driver is loaded. Multipath attempts to determine what the I/O paths are, which devices refer to the same WWID, and then (if whitelisted) map these to a single logical multipath device.

          So if multipath runs in a device error of sorts (as per your kernel log) - that error very likely comes from deeper down the driver stack.

          Can you flush and rerun multipath and post the output? E.g.
          // devices may not be in use
          [root@reuxeuls003 ~]# multipath -F
          
          // run multipath discovery with verbosity at level 3
          [root@reuxeuls003 ~]# multipath -v3
          • 2. Re: Help with Multipath
            691078
            Hi,

            I am not change /etc/udev/rules.d/40-multipath.rules file.
            Also I am not sending the output of "multipath -v3". Because output is too long.
            • 3. Re: Help with Multipath
              Billy~Verreynne
              Well, then you need to go line-by-line through that verbose output and see what the errors multipath runs into, trying to use the problem I/O paths (scsi devices).

              Or open a SR (service request) with Oracle to investigate the error - assuming you have an OL support agreement and a CSI number.
              • 4. Re: Help with Multipath
                898553
                I'm assuming this is on a CLARiiON since it's displaying DGC?