Asus P5W - Manual (Page 172)

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.