LSI MegaRAID SCSI 320-2 RAID Controller Series 518 - Manual (Page 26)

2-2 Introduction to RAID
Copyright © 2002 by LSI Logic Corporation. All rights reserved.
2.1.2 Increased Reliability
The electromechanical components of a disk subsystem operate more
slowly, require more power, and generate more noise and vibration than
electronic devices. These factors reduce the reliability of data stored on
disks. RAID provides a way to achieve much better fault tolerance and
data reliability.
2.2 MegaRAID SCSI 320-2 – Host-Based RAID Solution
RAID products are either host-based or external.
The MegaRAID SCSI 320-2 controller is a host-based RAID solution.
The MegaRAID SCSI 320-2 is a PCI adapter card that is installed in any
available PCI expansion slot in a host system.
2.2.1 Host-Based RAID
A host-based RAID product puts all of the RAID intelligence on an
adapter card that is installed in a network server. A host-based RAID
product provides the best performance. MegaRAID SCSI 320-2 is part of
the file server, so it can transmit data directly across the computer’s
buses at data transfer speeds up to 532 Mbytes/s.
The available sequential data transfer rate is determined by the following
factors:
•
The sustained data transfer rate on the motherboard PCI bus
•
The sustained data transfer rate on the PCI-to-PCI bridge
•
The sustained data transfer rate of the SCSI controller
•
The sustained data transfer rate of the SCSI devices
•
The number of SCSI channels
•
The number of SCSI disk drives
Host-based solutions must provide operating system-specific drivers.