Administrator's Guide

Virtualization

Virtualization allows you to subdivide each logical drive into one or more virtual disks, known as virtual logical units (VLUNs). These VLUNs can then be allocated for use by other computers in the network. These computers are known as iSCSI clients.

The Virtualization panel is divided into two subpanels: the VLUNs tree containing a list of all logical drives and VLUNs and the table that shows information about the selected item.

Adding a virtual logical unit

Each IBM IP Storage appliance can manage a maximum of 256 VLUNs. Each VLUN is created in increments of 1 GB.

Attention: After you create a VLUN, it cannot be resized or removed individually.

To create a VLUN in a logical drive using the Administrative Console:

  1. Click Storage --> Virtualization.
  2. Click the logical drive to which you want to add a VLUN. The amount of available space is shown next to the logical drive in the VLUNs tree.
  3. Click Add VLUN.
  4. Type the size, in gigabytes, of the VLUN in the VLUN Size field.
  5. Type the number of VLUNs to create in the # of VLUNs field.
  6. Click Add. The new VLUNs appear in the VLUNs tree.
  7. Click Apply.

Removing all virtual logical units from a logical drive

All VLUNs in the logical drive must be unassigned before performing this task.
Note:You cannot remove VLUNs if an iSCSI client that is assigned to at least one VLUN in the logical drive is currently logged on.

Attention: All data is lost when you remove VLUNs from the logical drive.

To remove all VLUNs in a logical drive using the Administrative Console:

  1. Click Storage --> Virtualization.
  2. Click the logical drive from which you want to remove all VLUNs.
  3. Click Remove VLUNs.
  4. Click Remove to verify the removal of all VLUNs from this logical drive. The VLUNs are removed from the VLUNs tree.
  5. Click Apply.
  6. If the iSCSI client is logged on, you are asked whether to force the iSCSI client to be disconnected. Click Yes to disconnect the iSCSI client.

Assigning an iSCSI client to a virtual logical unit

A VLUN is not accessible until you assign an iSCSI client to it. The user associated with that iSCSI client can then map to the VLUN as a network drive. The IBM IP Storage appliance supports a maximum of 1024 assignments. There is no limit to the number of assignments for each VLUN.
Note:A maximum of 16 clients can be logged on to the Model 100 at one time. A maximum of 32 clients can be logged on to the Model 200 at one time.

Unless the iSCSI client's operating system or applications support file sharing, only one iSCSI client should be assigned to a VLUN.

The maximum number of VLUNs that you can assign to a single iSCSI client is:

Windows 2000
254
Windows NT
8
Linux
16

The iSCSI client is identified by a unique ID (for example, the iSCSI client's host name). The ID is an ASCII string of up to 64 characters. The string can contain alphanumeric characters, periods (.), hyphens (-), and underscores (_). After you identify an ID, it appears in the drop-down list for the client IDs.

Each iSCSI client is limited to a single ID. If multiple VLUNs are assigned to a single iSCSI client, the same client ID must be used to access the VLUNs.

Setting a password is optional. If you specify a password for the iSCSI client, the iSCSI client is identified by both the ID and password. If the password field is left blank, only the client ID is verified. Only one password can be assigned to each iSCSI client ID. The password can be up to 16 characters. The string can contain alphanumeric characters, periods (.), hyphens (-), and underscores (_).

An iSCSI client logical-unit number (iLUN) is a unique number that is assigned automatically to each VLUN. The iLUN for a single client starts at 0 and increments sequentially. You can override this assignment; however, when a client is unassigned from a VLUN, the assignment of client logical-unit number for the remaining VLUNs is not changed.

Attention: Unassigning an iSCSI client from a VLUN might create problems on the iSCSI client because most operating systems expect the iLUNs to appear sequentially. Reassignment of iLUNs might also cause problems if the iSCSI client's operating system has certain signatures on the logical units. It is recommended that you evaluate and remedy the ramifications of unassigning an iSCSI client from a VLUN.
Note:Each iSCSI client must have an iLUN 0.

To assign an iSCSI client to a VLUN using the Administrative Console:

  1. Click Storage --> Virtualization.
  2. Click the VLUN to which you want to assign an iSCSI client.
  3. Click Assign client.
  4. Type a user name in the Login ID field or select an existing name from the drop-down list.
  5. Type the same password in the Password and Password Confirm fields.
    Note:If the user name already exists, you cannot edit these fields.
  6. Click OK to assign an iSCSI client to the VLUN. The user name appears under the VLUN in the VLUNs tree.
  7. Click Apply.

Unassigning an iSCSI client from a virtual logical unit

You can unassign an iSCSI client from a VLUN if it is not being used currently by the iSCSI client. All data is cleared, and the VLUN can be assigned to another iSCSI client.
Note:You cannot unassign an iSCSI client that is currently logged on.

To unassign an iSCSI client from a VLUN using the Administrative Console:

  1. Click Storage --> Virtualization.
  2. Click the iSCSI client you want to remove.
  3. Click Unassign client.
  4. Click Unassign to verify that you want to unassign the iSCSI client.
  5. Click Apply.
  6. If the iSCSI client is logged on, you are asked whether to force the iSCSI client to be disconnected. Click Yes to disconnect the iSCSI client.

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