Edge10 DAS401 用户指南

 

2   AN INTRODUCTION TO RAID 

 

 

VOLUMES 

 

RAID technology allows one or more disks to be combined into a logical volume which provides greater 

performance and/or protection than standard disk drives. These volumes, also known as RAID Groups, appear 

like regular disk drives to the operating system and can be partitioned, formatted and used just like any other 

normal disk. The complexity of the RAID is hidden within the driver. 

There are several different methods of combining disks, each with its own advantages and disadvantages.    Each 

method is referred to as a RAID “level” such as RAID 1, or RAID 5.    The details of each level are summarized 

below and detailed in the following sections. 

 

 

 

 

 

 

 

 

 

0

 

Striped

 

Excellent performance, low cost

 

No data protection

 

1

 

Mirrored

 

Excellent data protection

 

High cost

 

10

 

Mirrored Striped

 

High performance, excellent data 
protection.

 

High cost.

 

5

 

Parity RAID

 

Good data protection, good value

 

Some performance degradation 
for writes.

 

Combination

 

Concatenated

 

Good performance, low cost, large
Volume size

 

No data protection

 

Single Drive / Segment

 

Contiguous

 

Same as single disk

 

Same as single disk

 

 

DISKS 

 

For increased versatility, the SATARAID5 software allows individual disks to be divided into smaller segments 

which can then be combined into different volumes.    As an example, if a user has one set of data that must 

be protected at all costs, another set of data which should be protected at reasonable cost and another set 

that 

doesn’t need any protection at all; the user can divide three disks into sections as shown in Figure 1.    The yellow 

 

regions define the high security volume, the greem section is the middle security volume and the light blue shows 

the unprotected area. 

 

 

Figure 1:    Dividing Disks into Members 

DAS401 User’s Manual 

Ver.071015 

 

7