# Creating logical drives

Complete the following steps to create logical drives:

1. Click the appropriate Array tab.

2. In the Name field, type the logical drive name. The name must begin with an upper- or lower-case letter (a-z, A-Z).
3. Select a RAID level from the drop-down list.
   Notes:
   - If you are configuring a spanned array, you can set the RAID level only for the first logical drive you create.
   - In addtion to the standard RAID levels (0, 1, 5, x0), you can also create a simple volume: a single disk drive, non-redundant.
4. If you do not want to use the maximum size for the logical drive, type the size in the Data (MB) field.
   Notes:
     1. Some operating systems have size limitations for logical drives. Before you save the configuration, verify that the size of the logical drive is appropriate for your operating system. For more detailed information, see your operating-system documentation.
     2. A logical drive cannot exceed 2 terabytes (TB); the minimum size is 10MB.
     3. Typically, the first logical drive defined on the first controller found by system BIOS during startup will be your startup (boot) drive.
     4. The actual logical-drive size might be slightly different from what you select. The RAID level and the number of physical drives determine the size of the logical drive. For example, an array consisting of three, 1 GB physical drives with a requested RAID level-0 logical drive of 1000 MB will actually contain only 999 MB because the data is striped across all three drives, with 333 MB on each drive.
5. From the Stripe Size drop-down list, select the stripe-unit size for the logical drive.

   Note: The default stripe-unit size is usually adequate for most applications.

6. From the Controller drop-down list, select the preferred owner for the logical drive, Controller A or Controller B. (For single controller configurations, this field is grayed out.)
   Note: You can only choose the controller for the first logical drive in the array.
7. If you have free space available and want to create additional logical drives, click . To create a new logical drive with the same settings as the current logical drive, click ; then, choose the number of replicas from the drop-down list.
   Attention: Use care when allocating space for new a new logical drive. You must leave enough space for FlashCopy backups to grow to their virtual size. For example, if the virtual size of a FlashCopy backup is 20 GB, you must leave at least 20 GB of free space in the array. Note that the Configuration wizard displays the actual size of the first FlashCopy backup (not the virtual size), and 0 for all other FlashCopy backups.
8. Repeat steps 2 through 6 for each logical drive that you want to define in this array.
9. Repeat steps 1 through 7 for each additional array you want to configure.
10. Click Next. Depending on the initiator type, the "Define authentication method" window opens or the "Define initiators" window opens.

To return to the "Create arrays" window, click Back.
To leave the Configuration wizard, click Cancel.

## More information

- Example: Logical drive configurations
- Selecting the RAID level by array capacity
- Selecting the logical drive size
- Understanding physical drive capacity and unusable capacity

Glossary | Contents

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