Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 18)

Chapter 1. Introducing the LSI 3ware SATA+SAS RAID Controller Card
6 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
capacity into one large volume. Striped disk arrays (RAID 0) achieve
highest transfer rates and performance at the expense of fault tolerance.
• Distributed Parity . Parity works in combination with striping on RAID 5,
RAID 6, and RAID 50. Parity information is written to each of the striped
drives, in rotation. If a failure occurs, you can reconstructed the data on
the failed drive from the data on the other drives.
• Hot Swap . The process of exchanging a drive without shutting down the
system. This process is useful when you need to exchange a defective
drive in a redundant unit.
• Array Roaming. The process of from a controller and putting it back
either on the same controller, or a different controller, and having the unit
recognized as a unit. You can attach the disks to different ports without
harm to the data.
Available RAID Configurations
RAID is a method of combining several hard drives into one unit. It can offer
fault tolerance and higher throughput levels than a single hard drive or group
of independent hard drives. LSI's 3ware controllers support RAID 0, 1, 5, 6,
10, 50, and Single Disk. The following information explains the different
RAID levels.
RAID 0
RAID 0 provides improved performance, but no fault tolerance. Because the
data is striped across more than one disk, RAID 0 disk arrays achieve high
transfer rates because they can read and write data on more than one drive
simultaneously. You can configure the stripe size during unit creation.
RAID 0 requires a minimum of two drives.
When drives are configured in a striped disk array (see Figure 2), large files
are distributed across the multiple disks using RAID 0 techniques.
Striped disk arrays give exceptional performance, particularly for data-
intensive applications such as video editing, computer-aided design, and
geographical information systems.
RAID 0 arrays are not fault tolerant. The loss of any drive results in the loss of
all the data in that array, and can even cause a system hang, depending on
your operating system. RAID 0 arrays are not recommended for high-
availability systems unless you take additional precautions to prevent system
hangs and data loss.