Multipath (iSCSI) no Oracle Linux/Red Hat Enterprise Linux 5.11
  1. Instale o multipath:

    yum install device-mapper-multipath
  2. Crie o arquivo /etc/multipath.conf:
    # This is a basic configuration file with some examples, for device mapper
    # multipath.
    # For a complete list of the default configuration values, see
    # /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf.defaults
    # For a list of configuration options with descriptions, see
    # /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf.annotated
    #
    # REMEMBER: After updating multipath.conf, you must run
    #
    # service multipathd reload
    #
    # for the changes to take effect in multipathd
    
    # Blacklist all devices by default. Remove this to enable multipathing
    # on the default devices.
    blacklist {
            devnode "/dev/vda"
    }
    
    ## By default, devices with vendor = "IBM" and product = "S/390.*" are
    ## blacklisted. To enable mulitpathing on these devies, uncomment the
    ## following lines.
    #blacklist_exceptions {
    #       device {
    #               vendor  "IBM"
    #               product "S/390.*"
    #       }
    #}
    
    ## Use user friendly names, instead of using WWIDs as names.
    #defaults {
    #       user_friendly_names yes
    #}
    ##
    ## Here is an example of how to configure some standard options.
    ##
    #
    defaults {
            udev_dir                /dev
            polling_interval        10
            path_selector           "round-robin 0"
            path_grouping_policy    multibus
            getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
            prio                    none
            path_checker            readsector0
            rr_min_io               100
            max_fds                 8192
            rr_weight               priorities
            failback                immediate
            no_path_retry           fail
            user_friendly_names     yes
    }
    ##
    ## The wwid line in the following blacklist section is shown as an example
    ## of how to blacklist devices by wwid.  The 2 devnode lines are the
    ## compiled in default blacklist. If you want to blacklist entire types
    ## of devices, such as all scsi devices, you should use a devnode line.
    ## However, if you want to blacklist specific devices, you should use
    ## a wwid line.  Since there is no guarantee that a specific device will
    ## not change names on reboot (from /dev/sda to /dev/sdb for example)
    ## devnode lines are not recommended for blacklisting specific devices.
    ##
    #blacklist {
    #       wwid 26353900f02796769
    #       devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
    #       devnode "^hd[a-z]"
    #}
    #multipaths {
    #       multipath {
    #               wwid                    3600508b4000156d700012000000b0000
    #               alias                   yellow
    #               path_grouping_policy    multibus
    #               path_checker            readsector0
    #               path_selector           "round-robin 0"
    #               failback                manual
    #               rr_weight               priorities
    #               no_path_retry           5
    #       }
    #       multipath {
    #               wwid                    1DEC_____321816758474
    #               alias                   red
    #       }
    #}
    #devices {
    #       device {
    #               vendor                  "COMPAQ  "
    #               product                 "HSV110 (C)COMPAQ"
    #               path_grouping_policy    multibus
    #               getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
    #               path_checker            readsector0
    #               path_selector           "round-robin 0"
    #               hardware_handler        "0"
    #               failback                15
    #               rr_weight               priorities
    #               no_path_retry           queue
    #       }
    #       device {
    #               vendor                  "COMPAQ  "
    #               product                 "MSA1000         "
    #               path_grouping_policy    multibus
    #       }
    #}
  3. Configure a inicialização automática do serviço multipathd:
    chkconfig multipathd on
  4. Inicie o serviço multipathd:
    /etc/init.d/multipathd start
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