LaCie FIREWIRE 800/400 Understanding RAID, Raid, Recommended Uses, Characteristics and Advantages

LaCie Biggest Quadra	Understanding RAID
User Manual	page 16

3. Understanding RAID

Your LaCie Biggest Quadra is shipped with a pre- configured RAID level of 5, but it supports four dif- ferent RAID levels: 0, 0 + 1, 5 and 5 + Hot Spare. This section will help you decide which RAID level is right for you.

3.1. RAID 0

Striped Disk Array Without Fault Tolerance

Also called striping, this level offers high transfer rates and is ideal for large blocks of data where speed is of the utmost importance. RAID 0 implements a striped disk array, where all of the hard disks are linked together to form one large aggregate hard disk. In this configuration, data is broken down into blocks and each block is written to a separate disk drive within the array; I/O performance is greatly improved by spreading the I/ O load across several drives. In this array, however, when one disk fails, all of the data on the array is lost.

Storage capacity is determined by the smallest disk in the array, and the smallest disk’s capacity is applied to all of the other disks in the array. So, for instance, if you had four disks installed, ranging in capacity from 40GB to 80GB, when the RAID 0 array is built your system will see one, 160GB (40GB x 4) hard disk.

While this is a very simple and easily implemented design, RAID 0 should never be used in mission criti- cal environments. When even just one disk in the array fails, all of the data on the entire array will be lost.

■Recommended Uses

❖Video production and editing

❖Image editing

❖Pre-press applications

❖Applications requiring high-bandwidth

■Characteristics and Advantages

❖Data is broken down into blocks and each block is written to a separate disk drive

❖I/O performance improved by spreading the load across multiple drives

❖Overhead is lowered due to no calculations for parity

❖Simple design and easily implemented

This diagram represents a

E	RAID 0 array, consisting of
	four disks, which are
D
	connected to the Controller.
C	Data blocks are distributed

Bacross all of the disks in the

A array.

CONTROLLER

A	B	C	D	Fig. 3.1.
E	F	G	H
I	J	K	L
M	N	O	Etc...