src/ceph/doc/rbd/iscsi-initiator-rhel.rst

   1 ------------------------------------------------
   2 The iSCSI Initiator for Red Hat Enterprise Linux
   3 ------------------------------------------------
   4
   5 **Prerequisite:**
   6
   7 -  Package ``iscsi-initiator-utils-6.2.0.873-35`` or newer must be
   8    installed
   9
  10 -  Package ``device-mapper-multipath-0.4.9-99`` or newer must be
  11    installed
  12
  13 **Installing:**
  14
  15 Install the iSCSI initiator and multipath tools:
  16
  17    ::
  18
  19        # yum install iscsi-initiator-utils
  20        # yum install device-mapper-multipath
  21
  22 **Configuring:**
  23
  24 #. Create the default ``/etc/multipath.conf`` file and enable the
  25    ``multiapthd`` service:
  26
  27    ::
  28
  29        # mpathconf --enable --with_multipathd y
  30
  31 #. Add the following to ``/etc/multipath.conf`` file:
  32
  33    ::
  34
  35        devices {
  36                device {
  37                        vendor                 "LIO-ORG"
  38                        hardware_handler       "1 alua"
  39                        path_grouping_policy   "failover"
  40                        path_selector          "queue-length 0"
  41                        failback               60
  42                        path_checker           tur
  43                        prio                   alua
  44                        prio_args              exclusive_pref_bit
  45                        fast_oi_fail_tmo       25
  46                        no_path_retry          queue
  47                }
  48        }
  49
  50 #. Restart the ``multipathd`` service:
  51
  52    ::
  53
  54        # systemctl reload multipathd
  55
  56 **iSCSI Discovery and Setup:**
  57
  58 #. Discover the target portals:
  59
  60    ::
  61
  62        # iscsiadm -m discovery -t -st 192.168.56.101
  63        192.168.56.101:3260,1 iqn.2003-01.org.linux-iscsi.rheln1
  64        192.168.56.102:3260,2 iqn.2003-01.org.linux-iscsi.rheln1
  65
  66 #. Login to target:
  67
  68    ::
  69
  70        # iscsiadm -m node -T iqn.2003-01.org.linux-iscsi.rheln1 -l
  71
  72 **Multipath IO Setup:**
  73
  74 The multipath daemon (``multipathd``), will set up devices automatically
  75 based on the ``multipath.conf`` settings. Running the ``multipath``
  76 command show devices setup in a failover configuration with a priority
  77 group for each path.
  78
  79 ::
  80
  81     # multipath -ll
  82     mpathbt (360014059ca317516a69465c883a29603) dm-1 LIO-ORG ,IBLOCK
  83     size=1.0G features='0' hwhandler='1 alua' wp=rw
  84     |-+- policy='queue-length 0' prio=50 status=active
  85     | `- 28:0:0:1 sde  8:64  active ready running
  86     `-+- policy='queue-length 0' prio=10 status=enabled
  87       `- 29:0:0:1 sdc  8:32  active ready running
  88
  89 You should now be able to use the RBD image like you would a normal
  90 multipath’d iSCSI disk.