Logic MegaRAID SCSI 320-1 RAID Controller User's Guide

5-10 Configuring Physical Drives, Arrays, and Logical Drives

Note: The Megaraid SCSI 320-1 controller supports a maximum

of 15 physical drives.

5.3.1.2 Maximizing Drive Availability

You can maximize the availability of data on the physical disk drive in the

logical array by maximizing the level of fault tolerance. Tabl e 5.5

describes the levels of fault tolerance for the RAID levels.

5.3.1.3 Maximizing Drive Performance

You can configure an array for optimal performance. But optimal drive

configuration for one type of application will probably not be optimal for

any other application. A basic guideline of the performance

10 Mirroring and

Striping

4 – 14

(Must be a

multiple of 2.)

(Number of disks) X (capacity of

smallest disk) / (2)

50 RAID 5 and

Striping

6 – 15 (Must

be a multiple

of the

number of

arrays.)

(Number of disks) X (capacity of

smallest disk) – (capacity of 1 disk X

number of Arrays)

Table 5.4 Capacity for RAID Levels (Cont.)

RAID

Level Description

Drives

Required Capacity

Table 5.5 Fault Tolerance for RAID Levels

RAID Level Fault Tolerance Protection

0 No fault tolerance.

1 100% protection through data mirroring.

5 100% protection through striping and parity. The data is striped

and parity data is written across a number of physical disk

drives.

10 100% protection through data mirroring.

50 100% protection through data striping and parity. All data is

striped and parity data is written across all drives in two or

more arrays.