AMCC 9000 User Manual

Determining What RAID Level to Use

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Disk as a replacement for JBOD, to take advantage of advanced 
features such as OCE, and RLM. 

JBOD units are not fault tolerant and therefore not 
recommended for high availability systems unless additional 
precautions are taken to prevent system hangs and data loss. 

„

. A single drive, available online, so that a redundant 

array can be automatically rebuilt in case of drive failure. 

For additional information about RAID levels, see the article 
“RAID Primer” on the 3ware website, at: http://www.3ware.com/
products/pdf/RAID_Primer.pdf.

Other Important Concepts

„

. Used to store data locally on the drive before it is 

written to the disk, allowing the computer to continue with its 
next task. Enabling write cache results in the most efficient 
access times for your computer system. However, there may be 
instances when you always want the computer to wait for the 
drive to write all the data to disk before going on to its next 
task. In this case, you must disable the write cache. 

Determining What RAID Level to Use

The RAID configurations available to you are determined by the 
number of ports on your controller, and the number of drives 
attached to those ports. You can configure all drives in one array, or 
you can configure multiple arrays, if you have enough drives.

1

Single drive or hot spare