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4 silicon image, Raid configuration – Asus P5W User Manual

Page 172

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5-

Chapter 5: Software support

5.4.4

Silicon Image

®

RAID configuration

The Silicon Image

®

4723 Serial ATA controller allows you to build RAID sets on the

ASUS EZ-Backup Serial ATA hard disk drives.

About ASUS EZ-Backup

ASUS EZ-Backup is an ASUS exclusive feature that allows you to build a RAID set

easily. Without any configuration or BIOS setting required, you can create a RAID

1 set by simply plugging in two Serial ATA hard disks to the onboard EZ_RAID

connectors. Simply install the ASUS EZ-Backup Manager, and you are ready to

mirror your data. ASUS EZ-Backup secures your data and saves you from complex

configurations, troublesome setups, and complicated BIOS settings. Refer to the

succeeding sections to configure other RAID sets.

RAID modes supported

ASUS EZ-Backup supports the following RAID modes:
1. SAFE / RAID 1

(Data mirroring) is storage policy in which all data are stored

in duplicate on separate drives to protect against data loss due to drive

failure. One drive mirrors the other at all times. This mode is equivalent to

RAID 1. Every write operation goes to both drives. Safe provides the highest

level of data protection, but halves the amount of storage space because all

data must be stored twice.

If one drive fails, the Safe volume is in a vulnerable state because its mirrored

hard drive is inaccessible. When the offline drive comes back online, the

firmware begins a rebuild process immediately to restore data redundancy.

A message box appears in the ASUS EZ-Backup Manager graphical user

interface (GUI) to notify you that a rebuild is in progress. Although the volume

remains available during the rebuild process, the volume is susceptible

to data loss through damage to the remaining drive until redundancy is

restored at the end of the rebuild and verification process. Host access takes

precedence over the rebuild process. If you continue to use the Safe volume

during the rebuild, the rebuild process will take a longer time to complete.

To implement the Safe storage policy, the ASUS EZ-Backup Manager creates

one volume. One hard drive mirrors the other.

2. FAST / RAID 0

(Data striping) is a storage policy in which I/O processing

is balanced evenly in a method known as striping. This mode equivalent

to RAID 0. Striping increases storage operation speed because each

portion of data is divided into segments that are written to different disks

simultaneously. Fast offers the best performance, but no data redundancy

because there is no way to retrieve or reconstruct data on a failed drive.

To implement the Fast storage policy, the ASUS EZ-Backup Manager creates

a single volume that is striped across both hard drives.