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Creating a New Unit

When you create a new unit, you specify the following:

Drives to be included in the unit

You may include from one to twelve drives in the unit, depending on the number available.

You may only select available drives that are not currently part of a unit. If you want to use drives that are currently part of a different unit, you must delete that unit, first, to make the drives available. (For details, see Deleting a Unit.) If drives are listed under "Incomplete Drives and Others," they must be deleted before they can be used.

If you want to add drives to be used in the unit, see Adding a Drive through 3DM.

Type of configuration

Available configuration types include RAID 0, RAID 1, RAID 5, RAID 10, RAID 50, and Single Disk.

Note: Creating a unit erases all data on all drives. Although creating a RA1D 1 (mirror) creates a unit that will have a duplicate of data on both drives after it is put in use, creating a RAID 1 cannot be used to make a backup copy of data that currently exists on a single drive.

Stripe size, if appropriate for the RAID level

In general, smaller stripe sizes are better for sequential I/O, such as video, and larger strip sizes are better for random I/O (such as databases).

Striping size is not applicable for RAID 1, because it is a mirrored array without striping.

Using the default stripe size of 64KB usually gives you the best performance for mixed I/Os. If your application has some specific I/O pattern (purely sequential or purely random), you might want to experiment with smaller or larger stripe size.

To create a unit

  1. In 3DM, choose Management > Maintenance.
  2. In the Available Drives list, select the drives you want to include in the unit by marking the checkbox in front of the Port number for each one.
  3. If you are creating single drive units (single disks or hot spares), you can configure multiple drives at once.

    (For details about this screen, see Maintenance Page.)

  4. Click Create Unit.
  5. In the dialog box that appears, select the RAID configuration you want.
  6. If stripe size applies to the RAID type you select, select a Stripe Size.
  7. If you have 12 drives attached to the controller and selected RAID 50 as the configuration in step 3, select whether you want 3, 4, or 6 Drives Per Subunit.
  8. Click Ok.
  9. The new unit will appear in the Unit Maintenance list at the top of the page and the operating system will be notified of the new unit.

    In Linux, a device node will now be associated with each unit created. In Windows the device manager will reflect the changes under the disk drives icon.

  10. Partition and format the unit. (Steps will vary depending on the operating system.)
  11. Mount the new unit.
  12. Note: For RAID 5 units with 5 or more disks, and RAID 50 units with 10 or 12 disks and only two subunits, initialization of the unit begins immediately.

  13. Partition and format the unit. For details, see Partitioning and Formatting Units.

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