.. _Exporting Data via iSCSI:

Exporting Data via iSCSI
------------------------

Acronis Storage allows you to export cluster disk space to external operating systems in the form of LUN block devices over iSCSI in a SAN-like manner.

In Acronis Storage, you can create and run multiple iSCSI targets per Acronis Storage cluster node. In turn, each iSCSI target can have multiple LUNs (virtual disks). At any given moment, each iSCSI target runs on a single node. If a node fails, iSCSI targets hosted on it are moved to and re-launched on a healthy node.

The figure below shows a typical network configured for exporting Acronis Storage disk space over iSCSI.

.. image:: ../../../images/stor_image34.png
   :align: center
   :class: align-center
 
In this example there are three hardware nodes working in an Acronis Storage cluster. Two nodes host one iSCSI target each, while the third hosts two iSCSI targets. Each node has two network connections: one internal for cluster communication and one external for iSCSI exporting. Each iSCSI target has its own static IP address assigned from the datacenter network. The iSCSI network must be properly configured to run iSCSI targets. Each iSCSI target has a unique IP address from the iSCSI subnetwork different from the host IP address. So make sure you have a range of unused IP addresses for iSCSI targets.

.. _Creating Acronis Storage iSCSI Targets:

Creating Acronis Storage iSCSI Targets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note::

   1. Each iSCSI target must be assigned at least one unique IP address from DC network's static pool.

   2. The name of each iSCSI target must be unique in the Acronis Storage cluster.

   3. Acronis Storage iSCSI targets support persistent reservations to allow iSCSI initiators obtain exclusive access to the specified target's LUNs.

To create and start a target, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, click **ADD TARGET**.

2. On the **Add target** panel, type a name for the new target in the **Name** field.

   .. image:: ../../../images/stor_image35.png
      :align: center
      :class: align-center

3. In the node drop-down list, select a node on which the target will be located. The node should have an iSCSI role assigned to one of its network interfaces to appear in the list.

4. If necessary, check the **Enable CHAP** box and select an iSCSI user in the corresponding drop-down list (For more information on CHAP users, see :ref:`Managing iSCSI Users`).

5. Click **Add** to specify one or more IP addresses for the target.

6. Click **Done** to create the target.

The ISCSI target will be automatically started after creation and the initiators will be able to access the target via the specified IP address.

.. _Performance Tips:

Performance Tips
****************

- Spread iSCSI targets evenly across nodes in the cluster. For example, ten nodes with one iSCSI target per each will perform better than a single node with ten iSCSI targets on it.

- Fewer LUNs per more iSCSI targets will perform better than more LUNs per fewer iSCSI targets.

.. _Listing, Stopping, and Deleting Acronis Storage iSCSI Targets:

Listing, Stopping, and Deleting Acronis Storage iSCSI Targets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On the iSCSI targets screen, you can list and manage all iSCSI targets and their LUNs, and display detailed information about specific iSCSI targets registered on a node.

To stop or delete an iSCSI target, select it on the iSCSI targets screen and click **Stop** or **Delete**, respectively. Doing so will disconnect the iSCSI initiator from the target. However, breaking the connection in such a way may result in I/O errors on the iSCSI initiator's side.

.. _Configuring Acronis Storage iSCSI Targets:

Configuring Acronis Storage iSCSI Targets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To configure an iSCSI target, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, select the necessary target and click **Configure**.

2. On the **Configure** target screen, specify the necessary parameters.

   .. image:: ../../../images/stor_image36.png
      :align: center
      :class: align-center

3. Click **Done**.

.. _Listing LUNs:

Listing LUNs
************

In Acronis Storage, each iSCSI target can have multiple LUNs (virtual disks or volumes). You can list the LUNs of a target and iSCSI initiators that are currently connected.

To list the LUNs, open the **SERVICES** > **iSCSI** > **Targets** screen, select a target and click a link in the **LUNs** column.

To list the initiators that are currently connected to iSCSI targets, open the **INITIATORS** tab on the same screen.

.. _Adding LUNs:

Adding LUNs
***********

To add a LUN to an iSCSI target, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, select the necessary target and click a link in the **LUNs** column.

   .. image:: ../../../images/stor_image37.png
      :align: center
      :class: align-center

2. To add a new LUN to the list, click **ADD LUN**.

   .. image:: ../../../images/stor_image38.png
      :align: center
      :class: align-center

3. On the **Add LUN** screen, select the LUN's number from the drop-down list.

4. In the **LUN Size** field, specify the size of the LUN in GB; select a tier from the drop-down list to the right. For more information on tiers, see **Understanding Storage Tiers** in the *Acronis Storage 2.0 Installation Guide*.

5. From the **Failure domain** drop-down list, choose a placement policy for replicas. For more details, see **Understanding Failure Domains** in the *Acronis Storage 2.0 Installation Guide*.

6. Choose a data redundancy mode. For more details, see **Understanding Data Redundancy** in the *Acronis Storage 2.0 Installation Guide*.

7. Click **Done**.

.. _Configuring LUNs:

Configuring LUNs
****************

To configure a LUN of an iSCSI target, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, stop the target to which the LUN belongs.

2. Click a link in the target's **LUNs** column.

3. On the **Configure LUN** screen, specify the LUN size in the corresponding field.

4. Click **Done**.

.. _Deleting LUNs:

Deleting LUNs
*************

To delete a LUN, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, select the necessary target and click a link in the **LUNs** column.

2. Select the necessary LUN in the list and click **Delete**.

.. _Managing iSCSI Users:

Managing iSCSI Users
~~~~~~~~~~~~~~~~~~~~

.. _Creating CHAP Accounts for Acronis Storage iSCSI Targets:

Creating CHAP Accounts for Acronis Storage iSCSI Targets
********************************************************

To create a CHAP account, do the following:

1. On the **SERVICES** > **iSCSI Users** screen, click **Add user**.

2. Specify login, password, and, if necessary, a description for the account. The password should be 12 to 16 characters long for Windows clients to be able to establish connections.

   .. image:: ../../../images/stor_image39.png
      :align: center
      :class: align-center

3. Click **Done**.

The newly created CHAP user account will be listed on the **iSCSI Users** screen.

.. _Creating Acronis Storage iSCSI Targets Bound to CHAP Accounts:

Creating Acronis Storage iSCSI Targets Bound to CHAP Accounts
*************************************************************

To create an Acronis Storage iSCSI target bound to a CHAP account, do the following:

1. On the **SERVICES** > **iSCSI** > **Targets** screen, select an iSCSI target and click **Configure**.

2. On the **Configure** target screen, check **Enable CHAP** and/or **Enable mutual CHAP** and select users in the corresponding drop-down lists. If you enable CHAP, the target will authenticate the initiator. If you enable mutual CHAP, the initiator will authenticate the target. These options can be enabled in any combination.

   .. image:: ../../../images/stor_image40.png
      :align: center
      :class: align-center

3. Click **Done**.

.. _Changing CHAP Account Passwords:

Changing CHAP Account Passwords
*******************************

To change the password of a CHAP account, do the following:

1. On the **SERVICES** > **iSCSI Users** screen, select a user and click **Configure**.

2. In the **Password** section on the **Configure** user screen, click change.

   .. image:: ../../../images/stor_image41.png
      :align: center
      :class: align-center

3. Type a new password in the corresponding field and click **Done**. The password should be 12 to 16 characters long for Windows clients to be able to establish connection.

The new password will become active after target reboot.