Product manual

233
Chapter 7: Technology Background
• Introduction to RAID (below)
• Choosing a RAID Level (page 241)
• Stripe Size (page 244)
• Sector Size (page 244)
• Cache Policy (page 245)
• Capacity Coercion (page 246)
• Initialization (page 247)
• Hot Spare Drive(s) (page 247)
• Partition and Format the Logical Drive (page 248)
• RAID Level Migration (page 248)
• Media Patrol (page 250)
• Predictive Data Migration (PDM) (page 251)
• Transition (page 252)
Introduction to RAID
RAID (Redundant Array of Independent Disks) allows multiple hard drives to be
combined together in a disk array. Then all or a portion of the disk array is formed
into a logical drive. The operating system sees the logical drive as a single
storage device, and treats it as such. The RAID software and/or controller handle
all of the individual drives on its own. The benefits of a RAID can include:
• Higher data transfer rates for increased server performance
• Increased overall storage capacity for a single drive designation (such as, C,
D, E, etc.)
• Data redundancy/fault tolerance for ensuring continuous system operation in
the event of a hard drive failure
Different types of disk arrays use different organizational models and have
varying benefits. Also see Choosing RAID Level on page 241. The following
outline breaks down the properties for each type of RAID disk array: