MicroNet Technology MaxNAS manual Understanding RAID

5-Understanding RAID

Chapter 5- Understanding RAID

The MaxNAS controller subsystem is a high-performance SATA drive bus disk array controller. When properly configured, the RAID subsystem can provide non-stop service with a high degree of fault tolerance through the use of RAID technology and advanced array management features.

The RAID subsystem can be configured to RAID levels 0, 1 (0+1), and 5. RAID levels other than 0 are able to tolerate a Hard Disk failure without impact on the existing data, and failed drive data can be reconstructed from the remaining data and parity drives. RAID configuration and monitoring can be done through the LCD front control panel or serial port. The MaxNAS features the following high availability functions:

•RAID Levels 0,1,5,6 and Span support

•Global Online Spare

•Automatic Drive Failure Detection

•Automatic Failed Drive Rebuilding

•Hot Spare Disk Drives

•Instant Availability/Background

Initialization.

FYI:

The Berkeley RAID levels are a family of disk array data protection and mapping techniques described by Garth Gibson, Randy Katz, and David Patterson in papers written

while they were performing research into I/O subsystems at the University of California at Berkeley. There are six Berkeley RAID Levels, usually referred to by the names RAID Level 1, etc., through

RAID Level 6.

This section will help you gain

understanding of how these functions can serve your needs best.

RAID

RAID is an acronym for Redundant Array of Independent Disks. It is an array of multiple independent hard disk drives that provide high performance and fault tolerance through support of several levels of the Berkeley RAID techniques. An appropriate RAID level is selected when the volume sets are defined or created, and is based on disk capacity, data availability (fault tolerance or redundancy), and disk performance considerations. The RAID subsystem controller makes the RAID implementation and the disks’ physical configuration transparent to the host operating system, which means that the host operating system drivers and software utilities are not affected regardless of the RAID level selected.

RAID 0 (Striping)

This RAID algorithm writes data across multiple disk drives instead of just one disk drive. RAID 0 does not provide any data redundancy, but does offer the best high-speed data throughput. RAID 0 breaks up data into smaller blocks and then writes a block to each drive in the array.

Pros: Disk striping enhances both read and write performance because multiple drives are accessed simultaneously,

Cons: The reliability of RAID Level 0 is less than any of its member disk drives due to its lack of redundancy.

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