AMCC 9000 User Manual

Configuring Units

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 This section describes how to configure your 

RAID arrays as part of the installation process. For 
complete information about using 3ware BIOS Manager 
(3BM), including how to use it to change existing 
configurations, and for information about how to define 
and change the configuration using 3ware Disk Manager 
(3DM 2), see the 3ware 9000 Series Serial ATA RAID 
Controller User Guide. 

 You must attach drives before you can configure 

RAID arrays. If no drives are attached to the 3ware 
RAID controller, the 3ware BIOS will not be installed. 

Understanding RAID Concepts and 

Levels

The following concepts are important to understand when selecting 
the appropriate RAID level for a system:

„

. In the storage industry, the term “array” is 

used to describe two or more disk drives that appear to the 
operating system as a single unit. When you work with 3ware 
software, “unit” is the term used to refer to an array of disks 
that is configured and managed through the 3ware software. 
Single-disk units can also be configured in the 3ware software. 

„

. Mirrored arrays write data to paired drives 

simultaneously. If one drive fails, the data is preserved on the 
paired drive. Mirroring provides data protection through 
redundancy. In addition, mirroring using a 3ware RAID 
controller provides improved performance because 3ware’s 
TwinStor technology reads from both drives simultaneously.

„

. Striping across disks allows data to be written and 

accessed on more than one drive, at the same time. Striping 
combines each drive’s capacity into one large volume. Striped