How To: Backup to MyCloud EX4 NAS via iSCSI

WD EX Storage NAS


The WD EX Storage NAS can be used as an iSCSI Target for WD Arkeia network backup software installed on a Linux operating system. The Linux OS can be hosted as a Virtual or Stand Alone Physical machine.

iSCSI Storage Internet SCSI (iSCSI) is an industry standard developed to enable transmission of iSCSI block storage commands and data over an existing IP network by using the TCP/IP protocol. The encapsulated iSCSI commands and data can be transmitted over a local area network (LAN) or a wide area network (WAN).

As with traditional iSCSI, an iSCSI storage solution requires at least one “initiator” residing on the client computer and at least one “target” residing on the storage server. Once the connection is established between the iSCSI initiator and the iSCSI target, the operating system on the iSCSI initiator sees the storage as a local storage device that can be formatted, read, and written in the usual manner.


WD EX4 Storage Quick Installation Guide
WD EX4 Storage NAS User Manual

Static IP Address

The EX Storage NAS should be configured with a static IP Address to prevent Disk Storage backup failures.

How to configure WD EX Storage NAS with a Static IP Address

Configure NAS iSCSI Target

Reference WD EX4 Storage Quick Installation Guide
In the configuration below, CHAPS login is not used.



iSCSI Target Information

Click "Details" to access the Name and IP address of the target


Make a note of the information that will be used on the Linux System.


Linux iSCSI Initiator Configuration

Install the required iSCSI Initiator package

yum install iscsi-initiator-utils
sudo apt-get install open-iscsi

Start the iSCSI service

service iscsi start

Enable iSCSI service start on boot

chkconfig –-add iscsi
chkconfig iscsi on

Discover iSCSI Targets based on your EX NAS IP Address.

iscsiadm -m discovery -t sendtargets -p,1

Restart iSCSI

/etc/init.d/iscsi restart

Now there should be a block device under /dev directory.
To obtain new device name, type:

fdisk -l
tail -f /var/log/messages

scsi9 : iSCSI Initiator over TCP/IP
scsi 9:0:0:0: Direct-Access WD iSCSI Storage 3.5 PQ: 0 ANSI: 5
sd 9:0:0:0: [sdi] 1953125001 512-byte logical blocks: (1.00 TB/931 GiB)
sd 9:0:0:0: [sdi] Write Protect is off
sd 9:0:0:0: [sdi] Mode Sense: 3b 00 00 00
sd 9:0:0:0: [sdi] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sd 9:0:0:0: Attached scsi generic sg9 type 0
sdi: sdi1
sd 9:0:0:0: [sdi] Attached SCSI disk

Create Primary Partition on iSCSI Volume

fdisk /dev/sdi
Command (m for help): n
Command action
  e extended
  p primary partition (1-4)
Partition number (1-4): 1
First cylinder (1-36864, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-36864, default 36864): 36864

Command (m for help): p

Disk /dev/sdi: 38.6 GB, 38654705664 bytes
64 heads, 32 sectors/track, 36864 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

                       Device Boot Start End Blocks Id System
/dev/sdi 1 36864 37748720 83 Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

Format and Mount iSCSI Volume using EXT4

mkfs.ext4 /dev/sdi1

Create a mount point and mount the volume

mkdir /iscsi
mount -t ext4 /dev/sdi1 /isci

Edit the fstab file to auto mount the volume on boot.

vi /etc/fstab

/dev/sdi1 /iscsi ext4 _netdev 0 0

WD Arkeia Disk Storage

Create the WD Arkeia Disk Storage inside of the /iscsi volume mount and not directly on the mount itself.