Ninjas and Tigers

iscsi Discovery of Targets, repeat as many times as you have paths

iscsiadm -m discovery -t st -p <ip>

Log into the Target, repeat as many times as you have paths

iscsiadm -m node -T <iscsi target> -p <ip>:<port> –login

Check that All nodes now set up correctly

iscsiadm -m node

Check Sessions

iscsiadm -m session

Install multipath tools

aptitude install multipath-tools

Edit /etc/multipath.conf - Remember, this is for HITACHI, you may have to check Vendor

defaults {
  user_friendly_names yes
  pooling_interval 60
}
devices {
    device {
        vendor "HITACHI"
        product "DF600F"
        path_grouping_policy multibus
        path_checker tur
        no_path_retry 1
    }
}

blacklist {
    devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|sda|sdb|st)[0-9]*"
    devnode "^hd[a-z]"
    devnode "^sda"
}

Start multipath-tools

/etc/init.d/multipath-tools start

Check multipath is running and has correct stuffings

# /etc/init.d/multipath-tools start
Starting multipath daemon: multipathd.

# multipath -ll
mpath0 (360060e80105eecd00570775d00000001) dm-0 HITACHI,DF600F
 size=8.0T features='1 queue_if_no_path' hwhandler='0' wp=rw
 |-+- policy='round-robin 0' prio=1 status=active
 | `- 5:0:0:0 sdc 8:32 active ready running
 `-+- policy='round-robin 0' prio=0 status=enabled
   |- 6:0:0:0 sdd 8:48 active ready running
   `- 7:0:0:0 sde 8:64 active ready running

If you run into “No entry for device-mapper found*

multipath -ll
/proc/misc: No entry for device-mapper found
Is device-mapper driver missing from kernel?
Failure to communicate with kernel device-mapper driver.

This is due to dm-mod not being loaded, so you run

modprobe dm-mod

And then start multipath-tools

If it has been formatted on another platform, skip this section

Partitioning

NOTE : parted cannot be used with /dev/mapper/[dev_name] devices. Use parted on the underlying disks and execute the following command when device-mapper multipath maps the device to create a /dev/mapper/mpath[n] device for the partition.

# parted /dev/sdc
GNU Parted 2.3
Using /dev/sdc
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mklabel gpt
Warning: The existing disk label on /dev/mapper/mpath0 will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? y
(parted) mkpart
Partition name?  []? mailstorage
File system type?  [ext2]? ext4
Start? 0
End? 100%
Warning: The resulting partition is not properly aligned for best performance.
Ignore/Cancel? Ignore
(parted) print
Model: Linux device-mapper (multipath) (dm)
Disk /dev/sdc: 8796GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name         Flags
 1      17,4kB  8796GB  8796GB               mailstorage

Now remember this part, regardless

kpartx -a /dev/mapper/mpath0

If you haven't formatted yet

mkfs.ext4 /dev/mapper/mpath0p1

Mount it..

mount /dev/mapper/mpath0p1 <mountpoint>

Add it to /etc/fstab

/dev/mapper/mpath0p1 <mountpoint> ext4 rw	0	0

Update multipath configuration in initramfs

update-initramfs -u

.. you're now good to go..