ISCASI configuration for NAS

What is iSCSI and how can one benefits from it?
iSCSI, (Internet Small Computer System Interface), an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. iSCSI can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval. (quoted from Wikipedia)
An all-in-one storage solution with high ability of expansion and low establishment cost is alway seeked by most SMB storage infrastructure planners who have budget concerns and overall ease of delpoyment. With the iSCSI service on QNAP Turbo NAS it can instantly be served as your storage expansion or backup destination of the application servers, such as database server, mail server, or Time Machine (for Mac OS X 10.5 or later) in the business environment. This article demonstrates how you can use the iSCSI target service on QNAP NAS for storage expansion on different operating systems. See below for the usage scenario.

Things to know before we start
In between the relationship of your computer and the storage device, your computer is called an 'initiator' because it initiates the connection to the device, which is called a 'target'.

Note: It is NOT suggested to connect to the same iSCSI target with two different clients (iSCSI Initiators) at the same time, because this may lead to data crash or disk damage.

To begin, simply follow through the step-by-step guide below.

Create an iSCSI target volume

Log in to your QNAP NAS, go to 'Disk Management' > 'iSCSI' > 'iSCSI TARGET LIST' > 'Create New iSCSI Target' to create a new iSCSI target.

Refer to the image below to enter the required information to create the iSCSI target.

*Allocating the disk space ensures that an iSCSI Target has enough disk space as specified. However, the disk will take longer to create (depends on the given size) and there must be enough space on the physical disk.

Upon the successfull creation the iSCSI target will be shown on the iSCSI Target page and with status showing 'Ready'.

Advantages of Thin Provisioning on QNAP NAS With thin provisioning, the system administrator can flexibly allocate the disk space (on iSCSI Target) to the server applications to expand the storage capacity anytime regardless of their current storage size. The adding of the storage space on the servers can be easily done on different operation systems by the iSCSI initiator. Thin provisioning allows efficient storage management since the system administrator has to monitor only the storage capacity of one single server (QNAP NAS) rather than extra hard drives or tapes on other sub-storage systems. Over-allocation is allowed since the storage capacity of the NAS can be expanded by Online RAID Capacity Expansion

To connect to the iSCSI target we've just created select the tab representing the operating system you use to proceed.

Connect to the iSCSI targets by Microsoft iSCSI initiator on Windows

This article shows you how to use the iSCSI initiator on Windows to add the iSCSI target (QNAP NAS) as an extra partition. Before you start to use the iSCSI target service, make sure you have created an iSCSI target on the NAS in ‘Device Configuration' > ‘iSCSI Target' and installed the correct iSCSI initiator for your OS.
iSCSI Initiator on Windows
The Microsoft iSCSI Software Initiator v2.07 is an official application for Windows OS 2003, XP, and 2000 to allow users to implement an external iSCSI storage array over the network. If you are using Windows Vista or Windows Server 2008, the Microsoft iSCSI Software Initiator is included. For more information and the download location, please visit:
http://www.microsoft.com/downloads/details.aspx?familyid=12cb3c1a-15d6-4585-b385-befd1319f825&displaylang=en
Start iSCSI initiator from 'Control Panel' > 'Administrative Tools'. Under the 'Discovery' tab click on 'Add Portal'. Enter the NAS IP and the port number for the iSCSI service.

The available iSCSI targets and their status will then be shown under the 'Targets' tab. Select the target you wish to connect then click on 'Log on'.

You may click on 'Advanced' to specify the logon information if you have configured the authentication otherwise simply click on 'OK' to continue.

Upon successful logon, the status of the target now shows "Connected".

After the target has been connected Windows will detect its presense and treat it as if there was a new hard drive has been added which needs to be initialized and formated before we can use it. Right-click on 'My Computer' > 'Manage' to open the 'Computer Management' window then go to "Disk Management" and a window should pop-up automatically asking whether you wanna initialize the newly found hard drive. Click on OK then format this drive as normally you would when adding a new disk.

That's it! After disk initialization & formatting, the new drive is attached to your PC. You can now use this iSCSI target as a regular disk partition.