3DM 2 Online Help

Configuration Options When Creating a Unit
This section provides an overview of the choices you have when configuring a new unit. For step-by-step instructions, see Creating a Unit and “Creating a Unit through 3BM” on page 102.
When you configure a new unit, you specify the following:

| Drives to be included in the unit

| Type of configuration (RAID Level)

| Name of the unit (optional)

| Stripe size, if appropriate for the RAID level

| Unit policies that affect how the unit will be handled

You can make some types of changes to the RAID configuration later, and you can change the unit name and the unit policies. For details, see Changing An Existing Configuration by Migrating and Setting Unit Policies.

| Note: If you will install the operating system on and boot from a unit managed through the new 3ware RAID controller, see Chapter 3, “First-Time RAID COnfiguration” in the 3ware Serial ATA RAID Controller User Guide.

Drives to be included in the unit
You may include from one to sixteen drives in the unit, depending on the number of drives available and the model of the controller you have. (For information about how many drives to select for a given RAID level, see Determining What RAID Level to Use.)
Available drives are those that are not currently part of a unit. If you want to use drives that are currently part of a different unit, you must first delete that unit 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.
Type of configuration (RAID Level)
Available configuration types include RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50, and Single Disk. For information about the different RAID levels, see Understanding RAID Concepts and Levels.

| Note: Creating a unit erases all data on all drives. Although creating a RAID 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 unless you migrate from a RAID 1 to two individual single disks.

Name of the unit (optional)
Units can be given names. These names will be visible in 3DM and, 3BM.
Stripe size, if appropriate for the RAID level
In general, smaller stripe sizes are better for sequential I/O, such as video, and larger stripe 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 a smaller or larger stripe size.
Unit policies
Several unit policies are set when you create a new unit:

| Write Cache (enabled, by default)

| Drive Queuing (disabled, by default)

| Auto Verify (disabled, by default)

| Continue on Source Error During Rebuild (disabled, by default)

| StorSave Profile (Protection, by default)

The particular policies that you can adjust when you create the unit vary, depending on which program you are using: 3DM, 3BM, or the CLI.

| In 3DM and the CLI, you can enable/disable write cache, enable Auto-Verify, and specify whether to continue on source error

| In 3BM, you can specify all policies except Auto-Verify

You can change all of these policies after the unit has been created.
For a summary of what these policies do, see the discussion under Setting Unit Policies. For how to adjust each one, see the procedures later in this chapter.

Related Topics
  Creating a Unit
  Naming a Unit
  Enabling and Disabling the Unit Write Cache
  Setting Auto Verify for a Unit
  Setting Continue on Source Error During Rebuild
  Enabling and Disabling Queuing for a Unit
  Setting the StorSave Profile for a Unit
  Changing An Existing Configuration by Migrating

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