ceph/doc/rbd/iscsi-initiator-linux.rst

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