LSI Series 518 2.3.14 Disk Array Types, 2.3.15 Enclosure Management

2.3.14 Disk Array Types
	Table 2.4 describes the RAID disk array types.
	Table 2.4	Disk Array Types

	Type		Description

	Software-		The array is managed by software running in a host computer
	Based		using the host CPU bandwidth. The disadvantages associated
			with this method are the load on the host CPU and the need
			for different software for each operating system.

	SCSI to SCSI		The array controller resides outside of the host computer and
			communicates with the host via a SCSI adapter in the host.
			Array management software runs in the controller. It is
			transparent to the host and independent of the host operating
			system. The disadvantage is the limited data transfer rate of
			the SCSI channel between the SCSI adapter and the array
			controller.

	Bus-Based		The array controller resides on the bus (for example, a PCI or
			EISA bus) in the host computer and has its own CPU to
			generate parity and handle other RAID functions. A bus-based
			controller can transfer data at the speed of the host bus but is
			limited to the bus it is designed for. MegaRAID SCSI 320-2
			resides on a PCI bus, which can handle data transfer at up to
			132 Mbytes/s. With MegaRAID SCSI 320-2, the channel can
			handle data transfer rates up to 320 Mbytes/s per SCSI
			channel.

2.3.15 Enclosure Management

Enclosure management is the intelligent monitoring of the disk subsystem by software and/or hardware.

The disk subsystem can be part of the host computer or can be separate from it. Enclosure management helps you stay informed of events in the disk subsystem, such as a drive or power supply failure. Enclosure management increases the fault tolerance of the disk subsystem.

RAID Overview

2-11