Target Management

You can create multiple LUNs for an iSCSI target. In this chapter, the following topics are covered:

•	Creating iSCSI Targets

•	Switching LUN Mapping

•	iSCSI LUN Capacity Expansion

•	Optimizing iSCSI Performance

Creating iSCSI Targets

Note: The following information only applies to ARM-based NAS models with firmware version 3.3.0 or later and x86-based NAS models running firmware version 3.2.0 or later.

You can create multiple LUNs for an iSCSI target. Follow the steps below to create more LUNs for an iSCSI target.

1.	Click "Quick Configuration Wizard" under "Target Management".

2.	Select "iSCSI LUN only" and click "Next".

3.	Select the allocation method. Enter the name of the LUN, select the LUN directory, and specify the capacity for the LUN. Click "Next."

4.	Select the target to map the LUN to (optional).

5.	Confirm the settings and click "Next."

6.	When the LUN has been created, click "Finish" to exit the wizard.

7.	The LUNs can be mapped to and unmapped from the iSCSI target anytime. You can also unmap the LUN from a target and map it to another target.

Item	Status	Description
iSCSI target	Ready	The iSCSI target is ready but no initiator has connected to it yet.
	Connected	The iSCSI target has been connected by an initiator.
	Disconnected	The iSCSI target has been disconnected.
	Offline	The iSCSI target has been deactivated and cannot be connected by the initiator.
LUN	Enabled	The LUN is active for connection and is visible to authenticated initiators.
LUN	Disabled	The LUN is inactive and is invisible to the initiators.

Button	Name	Description
	Deactivate	Deactivate a ready or connected target. Note that the connection from the initiators will be removed.
	Activate	Activate an offline target.
	Modify	Modify the target settings: target alias, CHAP information, and checksum settings. Modify the LUN settings: LUN allocation, name, disk volume directory, etc.
	Delete	Delete an iSCSI target. All the connections will be removed.
	Disable	Disable an LUN. All the connections will be removed.
	Enable	Enable an LUN.
	Unmap	Unmap the LUN from the target. You must disable the LUN before unmapping it. When you click this button, the LUN will be moved to "Un-Mapped iSCSI LUN List".
	Map	Map the LUN to an iSCSI target. This option is only available on the "Un-Mapped iSCSI LUN List".
	View	View the connection status of an iSCSI target.

Switching LUN Mapping

Note: The following information only applies to ARM-based NAS models with firmware version 3.3.0 or later and x86-based NAS models running firmware version 3.2.0 or later.

Follow the steps below to switch the mapping of an iSCSI LUN.

1.	Select an iSCSI LUN to unmap from an iSCSI target and click "Disable".

2.	Click "Unmap" and the LUN will appear on the Un-Mapped iSCSI LUN List. Click "Map" to map the LUN to another target.

3.	Select the target to map the LUN to and click "Apply"

4.	The LUN is mapped to the target.

After creating the iSCSI targets and LUN on the NAS, you can use the iSCSI initiator installed on your computer (Windows PC, Mac, or Linux) to connect to the iSCSI targets and LUN and use the disk volumes as the virtual drives on your computer.

iSCSI LUN Capacity Expansion

The NAS supports expanding the capacity of an iSCSI LUN. To do so, follow the steps below.

1.	Locate an iSCSI LUN on the iSCSI target list in "iSCSI" > "Target Management". Click "Modify".

2.	Specify the capacity of the LUN. Note that the LUN capacity can be increased many times up to the maximum limit but cannot be decreased.

3.	Click "Apply" to save the settings.

Note:

•	An iSCSI LUN must be mapped to an iSCSI target before increasing the capacity.

•	For the type of LUN allocation, the maximum LUN capacity for thin provisioning is 32TB, while for instant allocation, the maximum LUN capacity is limited by the available free space on the disk volume.

Optimizing iSCSI Performance

In the environments that require high performance storage, such as virtualization, users are recommended to do the following to optimize the iSCSI and NAS hard disks performance:

•	Use instant allocation: When creating an iSCSI LUN, select "Instant Allocation" to achieve slightly higher iSCSI performance. However, the benefits of thin provisioning will be lost.

•	Create multiple LUNs: Create multiple LUNs according to the number of processors on the NAS (this can be found in "System Status" > "Resource Monitor".) If the NAS has four processors, it is recommended to create four or more LUNs to optimize iSCSI performance.

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Use different LUNs for heavy load applications: Spread applications such as databases and virtual machines that need high read/write performance to different LUNs. For example, if there are two virtual machines which intensively read and write data on LUNs, it is recommended to create two LUNs so that the VM workloads can be efficiently distributed.

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