Configure Network Settings for iSCSI Target Device
The Dell PowerVault NX1950 is configured to use DHCP for its default network settings. The basic unit is designed for multi-path operations and is equipped with four RJ45 Ethernet connectors. The initial configuration screen shows the basic settings.
All the storage management functions for the Dell PowerVault NX1950 are performed from the management console, shown below.
At the top of the center section of the management console, several scenarios are available that help step the administrator through each of the processes.
Create LUNs on Disk Array
To create the LUNs on the Disk Array, the administrator selects the “Provision Storage and Create Volume” scenario from the upper section of the management console. This directs the administrator in the appropriate steps to take.
The right-side panel of the management console is context sensitive, and changes based on the item selected on the left side of the panel. Highlighting “Share and Storage Management” on the left panel console tree brings the “Provision Storage” wizard into view on the right side.
Selecting the “Provision Storage” action on the right side initializes the wizard for this function. The wizard allows the administrator to step through the provisioning process. Notice that the left side of the wizard lists each of the main steps in the process.
The storage subsystem must be selected and in this case there is only one subsystem to select. It is of type “Fibre Channel” because the internal interface to the disk subsystem is listed as Fibre Channel even if SAS is used. This will be changed in the next version.
The LUN type must be chosen from among the various types of LUNs available. In this example, we have chosen a “striped” LUN type. Each type of LUN has a maximum size that depends on the type.
Note – It is important at this point to note that the storage solution LUN size should not be confused with the size of the iSCSI target. The iSCSI target will be configured in a later step and is associated with the storage needed for a particular application on the host server. It is recommended that the LUN size on the storage hardware be as large as reasonably possible to allow the storage subsystem to optimize the use of the physical disks underlying the LUN that is created. In this case, as shown below, we are choosing to create one LUN at the maximum size available for this hardware. The iSCSI targets created later will fit into this one LUN, based on the needs of the host application.
The LUN created will be assigned to this internal storage server only. In a later step, iSCSI targets will be created that will be assigned to external application servers.
The name of this server needs to be provided for the assignment.
Make LUNs Ready for Use
Because this storage solution is running on a Microsoft Windows-based platform, the remaining steps would be familiar to a Windows administrator. This can be an advantage in environments where Windows is prevalent as it reduces specialized training needed for managing the storage devices. These include assigning a drive letter for the internal server, providing a volume name, etc. The wizard prompts for these items then provides a summary screen before performing all the necessary tasks to provision the storage.
After a short while, the following screen indicates a successful provisioning operation.
The LUN has now been created and is ready for use. The next step will create iSCSI targets and associate them with this newly-created LUN. This implementation of WUDSS uses the Microsoft Virtual Disk Service (VDS) internally on this server. The LUN can also be viewed in the Storage Manager for SANs section of the management console, as shown below.
Create iSCSI Targets
Moving to the iSCSI target section of the management console, a wizard can be triggered (using the right-mouse click) that begins the iSCSI target creation process.
The iSCSI target wizard is launched. In this case, we will create two iSCSI targets. Each target will be made available to a different application on the host server. The target itself in the Microsoft-based iSCSI target solutions merely defines the path that the iSCSI storage traffic will use from the iSCSI initiator. The actual storage used by the target will be defined in a later step when the virtual disks are created.
Each iSCSI target needs a name and optional description, which are supplied below.
Each iSCSI target needs to be associated with an iSCSI initiator. The iSCSI initiator is the host that is requesting access to the storage represented by the iSCSI target name. The wizard prompts for the iSCSI Qualified Name (IQN) of the iSCSI initiator or provides alternate ways to identify the iSCSI initiator. In this case, we will choose to identify the iSCSI initiator by its IP address.
Clicking “Advanced” allows us to choose alternate methods of identification.
Clicking “Add” allows the type of identifier to be entered and the specific identifying information to be entered.
After identifying the iSCSI initiator, we are ready to proceed.
The management console now shows the newly created iSCSI target.
The management console also shows the underlying devices available for the iSCSI targets. The storage that will be used by the iSCSI initiators (application hosts) will be defined in a later step when the virtual disks are created.
Create Multi-path I/O for iSCSI Targets (optional)
For a Microsoft-based target solution, multiple paths to the target device are created by providing multiple iSCSI initiator identifiers for the same target. Multiple paths to an iSCSI target can be creating by adding sessions to the iSCSI target (Microsoft MPIO) or adding additional connections to the iSCSI target (Multiple Connections per Session). In the example below, we use MS MPIO and add a second IP address that is to be associated with the same iSCSI initiator, so that there are two IP addresses that can access the target. These two addresses are associated with two Ethernet ports on the same host server.
Other steps will need to be taken on the iSCSI initiator side to complete the multi-path configuration.
Configure Security for iSCSI Targets (optional)
CHAP can be configured with a password also known as the “CHAP secret”. The CHAP secret provides an additional level of security between the iSCSI initiator and target. The CHAP secret is provided on the “Authentication” tab of the target properties.
Make iSCSI Targets Ready for Use for iSCSI Initiators
Virtual disks need to be created on the iSCSI targets for Microsoft-based iSCSI target solutions. These virtual disks represent the storage volumes that the iSCSI initiators will use. The maximum capacity represented by all the virtual disks on a given iSCSI target on a Microsoft-based iSCSI target solution is two terabytes (2 TB) per target. In this example, we create a 100 GB and 200 GB virtual disk on the iSCSI target. These two virtual disks will be viewed as volumes by the iSCSI initiators over the TCP/IP network.